Welcome to our live coverage of the build-up to the G20 summit in London, where world leaders are gathering in an attempt to agree solutions to the global economic crisis and protests are underway. We will be bringing you news, insights from BBC correspondents, some of your e-mails and Twitter, as well as the best of the blogs.
With G20 leaders enjoying supper, Climate Camp preparing for a night on a road and protesters at the Bank of England wondering when the police will let them go, that's it for today's live text coverage of the events leading up to the G20 summit. Live text coverage will resume at 0700 on Thursday. Delegates will begin arriving at 0730 and then it will be a mad dash to 1530 when Gordon Brown is due to deliver his closing statement.
North of the climate camp on Bishopsgate. It's completely hemmed in by police. Being a camp, they're prepared for the long haul.
Read Tristamsparks' tweets.
2039The BBC's Ross Hawkins at Downing Street says:
Something quite incredible is happening behind me: 20 incredibly powerful people trying to build relationships. What a remarkable chat around the dinner table it must be right now.
Opakunle Abayomi, Nigeria, says:
During this economic crisis jobs have been lost, people have cut their spending. The G20 protesters should be patient so that a lasting solution can be found.
Have your say
2025 The BBC's Robert Hall in Bishopsgate says:
Riot police have penned in the Climate Camp protesters on three sides. One of the organisers stressed that this is a 24-hour camp and they intend to be here until 1230 tomorrow.
2023 The BBC's Ben Brown in the City says:
There is now a stand-off between protesters and the police. The protesters are penned in - they want to leave, but the police won't let them.
The G20 leaders are gathered around the dinner table. News cameras catch them making preliminary chit-chat before the meal arrives.
2009The BBC's Ross Hawkins at Downing Street says:
France's President Nicolas Sarkozy has turned up for the meal 10 minutes late. It's always hard to tell the line between fashionably late and slightly rude but President Sarkozy was probably on it.
Andy James, Swansea, says:
I agree with the French and Germans. Why should future generations pay higher taxes? It's our problem - we should pay for it.
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Jamie Oliver is preparing tonight's meal despite the fact that his wife, Jools, is due to give birth to their third child imminently. For security reasons, the dad-to-be will have to hand over his mobile phone when he enters 10 Downing Street. But officials have promised to keep him informed should Jools go into labour.
While the leaders talk shop over dinner, their spouses will sit with stars of sport, business and the arts. US first lady Michelle Obama will be seated between Harry Potter author JK Rowling and Olympic gold medallist Dame Kelly Holmes.
The G20 leaders are in for a feast tonight. Chef Jamie Oliver is preparing a meal of Welsh lamb, Jersey Royal new potatoes and asparagus. Vegetarian heads of government can choose potato dumplings instead.
The Obamas are having their second Downing Street meal of the day
UN Secretary General Ban Ki Moon is the first G20 leader to arrive for the dinner at 10 Downing Street.
1922 The BBC's Mark Georgiou asks:
What happens now? The climate camp protestors want to spend the night on Bishopsgate and it looks increasingly like the police are not going to let that happen.
1915 The BBC's Robert Hall at Bishopsgate says:
There has been no violence here all day, but the trouble at the Bank of England has changed the atmosphere with police in the past 15 minutes. The police seem keen to prevent anyone at the peace camp leaving to join the protests at the Bank of England.
1910 The BBC's Ben Brown near the Bank of England says:
Protesters have set up barricades in the street and have lit a fire from which black smoke is billowing. Missiles are being thrown and the police have mounted a charge against protesters. There's some quite ferocious fighting going on.
A statement from Scotland Yard says that officers in the City "are now working towards a controlled dispersal, where groups of people will be allowed to leave".
1847 The BBC's Danny Shaw at Scotland Yard says:
Commander Simon O'Brien has told reporters that officers are collecting evidence about those involved in today's trouble. He said the Met will "pursue a post-event investigation" - people will be visited by police and arrested.
1841 The BBC's Ben Brown in the City says:
I've spoken to some protesters with blood on their faces. They say they can't get out to get those injuries treated because of the police cordon.
Finally released from captivity. What a bizarre experience. Will pack a lunch next time.
Read Kerryrm's tweets.
1812 The BBC's Dominic Casciani says:
I'm at the Bishopsgate climate camp and its fairly clear they want to be here for the rest of the night. There are loo tents, food stalls and discussion groups. There's some good music - and some lousy guitar playing. It feels like the summer festivals without the mud.
1802 The BBC's Rob Broomby near the Bank of England says:
Something of a siege taking place here now, provoking some clashes. People angry, but getting weary - they've been held in just a few narrow streets for a number of hours now.
1754The BBC's Justin Webb says:
The Obama team is extremely positive about the meeting between their man and Russian President Dmitry Medvedev. They say the meeting has changed the relationship between the US and Russia.
Standoff now on Queen Victoria Street. I'm between the police lines but think I might try for home.
Read Thecityblog's tweets.
1750The BBC's Peter Hunt says:
President Obama has given the Queen an Ipod during their private meeting at Buckingham Palace. It contains footage of her state visit to the US in May 2007. The Queen has given the president a silver framed photograph of herself and her husband. The official picture is what she gives all visiting dignitaries.
1739BBC royal correspondent Nicholas Witchell says:
There has been a real sense of anticipation at Buckingham Palace. The Obama stardust has penetrated even here.
I've seen two policemen in Trafalgar Square. Absolutely no violence here. Less police, less violence? Not that simple, but interesting
Read Mrfranks' tweets.
1734The BBC's Andy Tighe with Scotland Yard's Gold Command says:
Police say officers have suffered only minor injuries during the protests, although one is in hospital. The Met also insists that its response has been "proportionate".
1729The BBC's Stephanie Flanders says:
Don't believe the hype. They are still arguing over some parts of the agreement to be signed by G20 leaders tomorrow, but there's no grand ideological battle over the nature of capitalism, or anything else.
Barack and Michelle Obama arrive at Buckingham Palace in the Beast - the US President's limousine. They are greeted by courtiers and ushered inside.
1715The BBC's Rajini Vaidyanathan at Buckingham Palace says:
Crowds are lined up outside, cameras aloft in anticipation of the first couple. Security is as expected - those gathered to watch are behind a cordon, the sniffer dogs have been and gone too.
G20 protester: " I have a responsibility to be here"
French President Nicolas Sarkozy urges his fellow G20 leaders to "seize the historic moment" and build "regulation for the 21st century".
German Chancellor Angela Merkel tells a joint press conference with French President Nicolas Sarkozy that the crisis was "not a natural catastrophe" and calls for better regulation to tackle the "root causes" of the global downturn.
1654 The BBC's Ben Brown in the City says:
The demonstrators are not free to move around. The police are closing off street after street.
1653The BBC's Mark Georgiou says:
Until now the climate camp protest has had a peaceful, almost carnival atmosphere. However, in last half an hour a different sort of demonstrator has started to arrive - clad in black, masked and aggressive.
1650 The BBC's Dominic Hurst texts:
HSBC branch in Eastcheap attacked. Windows broken. Police regain control. Crowd moves on to Fenchurch Street.
Anon, London, says:
Yes I work in the City, yes I have come in in casual dress, but the one advantage being that I can join in with the peaceful demonstrators during my lunch break, which I will do.
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Paul Curtis took this photo of a protester in Leadenhall Street
James, London, says:
Do the protestors know the intrinsic idea of their protests or are they anarchists simply looking for a riot? Look at yourselves in the mirror in the morning and question whether you have made a difference to our country's direction. I can't wait to walk out proudly in my pinstripes today!
Have your say
All quiet on the EC2 front. Most people just enjoying the sound systems and juggling.
Read Tim's tweets.
1630The BBC's Dominic Hurst texts:
Interesting chatter on twitter at the moment. Some protestors are saying police are calm and fair and letting them have a good day out.
The Prime Minister's spokesman says the G20 leaders are making good progress but they are "not there yet". The spokesman adds that there is an "emerging degree of consensus... but there are still a number of issues that need ironing out".
1625 The BBC's Dominic Casciani says:
Its a completely different mood at Trafalgar Square. A few thousand people have come down here for the Stop the War Coalition march. It's a classic demo calling for troops out of Iraq, Afghanistan, a bit of Palestinian solidarity and a nuclear-free world.
1622The BBC's Rob Broomby says:
Pretty calm now outside the Bank of England. Police are standing off for the moment and what's left of the protesters are standing outside the Bank's gates, dancing and shouting.
The anti-war protesters gathered at Trafalgar Square sing Happy Birthday to veteran left-winger Tony Benn, who turns 84 on Friday. "We want democracy, freedom, justice and peace," he tells them.
1610 The BBC's Ben Brown on Threadneedle Street says:
Just after four o'clock, riot police charged the demonstrators. We don't know why, but there were some violent scenes.
Mr Matin, Singapore, says:
I strongly support President Sarkozy's demand for stricter financial regulations worldwide. The G20 meeting should control the hedge funds and eliminate if possible all sorts of short-selling in the stock market.
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Fatima Nuzzi, Gran Canaria, says:
The US and the UK are the main ones who caused this world economic problem and not only have they got away with it, but they are now turning it to their advantage. When a building falls down the architect is responsible and should pay for it.
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Coffee shop over the road must be getting a year's worth of takings today. Some of their just-bought produce promptly hurled at police line.
Read Unslugged 's tweets.
1601 The BBC's Dominic Hurst texts:
Standoff in Queen Victoria Street. Approx 50 police in riot gear surrounded by protesters chanting "our streets". Some pushing and missile throwing, but police holding the line.
More than 1,000 economists, academics and other notables have signed a letter urging G20 leaders to promote free trade and reject protectionism, which it insists "creates poverty, not prosperity... Protectionism is a fool's game".
1546The BBC's Justin Webb says:
Obama's meeting with Medvedev was hugely important. The Russians said they understood US concerns about Iran's nuclear programme, which suggests a real change in Russia's approach. Both sides are also starting talks on a new nuclear arms reduction deal.
1545 The BBC's Daniel Boettcher says:
Police outside the Bank of England are trying to disperse the protesters in an orderly fashion. They are opening junction after junction once they feel they are in control.
1540The BBC's Dominic Casciani says:
If the demonstrators set out to stop the City then they have succeeded. We've been walking down street after street as if cars don't exist. Police are hemming in protesters who they think might want a confrontation, but many others are drifting about looking for something to do.
Nigel, UK, says:
I work about 100 metres from where it's all happening. They aren't exactly storming the Bastille. It feels more like the first festival of the summer. I wish they'd come more often.
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Scotland Yard says 23 arrests have been made so far, including 11 in connection with possession of police uniforms, one for threatening behaviour, two for violent disorder, one for indecency and two for breach of the peace.
1530The BBC's Mark Georgiou says:
At the climate camp protest there is an almost Glastonbury atmosphere with music and meditation.
1525The BBC's Nick Childs outside Buckingham Palace where Barack Obama will meet the Queen later, says:
Barack Obama is really the man to see and be seen with, and there is already a crowd building up outside the Palace waiting for his arrival.
1510The BBC's Danny Shaw says:
Police sources say the mood has changed at the protest - now a lot calmer than it was before. Officers are starting to disperse some of the protesters, and will look out for people who are "of interest".
In a statement, the Royal Bank of Scotland says it had already taken the precaution of closing its Threadneedle Street branch, as well as other outlets in the City. "The safety of our employees and our customers is of paramount importance to us," it adds.
Vikki Chowney is one of the official bloggers inside the event. She tweets:
Interesting... Bob Geldof joining us tomorrow as a @g20Voice blogger.
Read Vikki Chowney's tweets.
The BBC's Dominic Casciani writes:
I am one of the BBC team roving around London. I would like to hear your stories and thoughts to get the mood and atmosphere beyond the main G20 event. You can get hold of me via twitter - user name @domcasciani.
Link to Dominic's tweets
1505The BBC's Tom Symonds says:
The cordon outside the Bank of England has been relaxed and protesters have been allowed to leave to the West.
Tom Cobbley, UK, says:
I am in the City right now and it's like a Sunday. Everyone's taken the day off, and other than a throng around Bank, it's like the Marie Celeste. And at what price is this one-day shut down to the economy?
Have your say
An injured officer near Liverpool Street (sent in by Natalie Barone)
Simon, UK, says:
I fully support people's right to demonstrate today. I'm also a banker mostly arranging finance for renewable energy schemes. I agree that the financial system needs some improvement. The City has overcome major challenges in the past and it will overcome the current problems too.
Have your say
1443The BBC's Stephanie Flanders says:
All the G20 leaders, including President Obama, will pledge tomorrow to support a much stronger system for warning of future crises. But do they realise quite how independent any new watchdog will need to be?
1441The BBC's Rob Broomby outside the Bank of England says:
Something of a standoff now. Police have pushed protesters further down Threadneedle Street. Two protesters managed to get on to the roof of the Bank of England. Police dogs brought in, police are in riot gear. Some protesters are hooded and wearing balaclavas - looking like they are here to cause trouble.
Russian President Dmitry Medvedev arrives at Downing Street, where he is met by Gordon Brown.
US President Obama and President Hu Jintao of China have agreed at a bilateral meeting the need for "sweeping changes" in the governance of international finance, according to a White House statement. Obama will visit China later this year.
China and US pledge co-operation
1417The BBC's Mark Georgiou says:
Police in riot gear are slowly clearing the area in front of RBS on Threadneedle Street. It is noisy and the occasional missle is thrown. One protestor has bared his backside to the police. I've not seen any arrests so far. Police seem happy just to contain crowd.
1412The BBC's Dominic Casciani at Bishopsgate says:
Calm here. Campers are putting up tents and police are not stopping them. Organisers say they will be here for 24 hours and food is being served. Organisers wearing sashes are announcng climate change workshops for anyone here for the long haul.
1405The BBC's Daniel Boettcher says:
A dozen or so police officers are putting on riot gear. On this corner of Threadneedle Street some of the protesters have been surging forward trying to push through the police line. The police have blocked off all approaches to the square, they are letting people out but no one back in again.
1352The BBC's Mark Georgiou texts:
More windows broken at RBS - some protestors in building. Mounted police blocking end of Bartholemew lane. More windows broken. Very tense.
BBC correspondents report that windows of a branch of Royal Bank of Scotland in the City have been broken.
Russian President Dmitry Medvedev says he is "optimistic" about future relations with the US after meeting Obama. Obama says he will visit Russia in July.
1342Rolf Goehler from Ilinois, US, writes:
The leaders are too incompetent to address any of these issues. This is a good political show for the dumb masses that think government is the solution.
BBC's Mark Georgiou texts:
Bottles and cans thrown at RBS on Threadneedle Street.
1315 BBC reporter Dominic Casciani says:
Climate Camp protesters have occupied Bishopsgate outside the Climate Exchange, where carbon emission permits are traded. Atmosphere is carnival-like among at least 500 people - police are invisible other than vans shielding the exchange offices.
1315 BBC reporter Ben Brown outside the Bank of England says:
Protesters have been scrawling graffiti on the walls of the Bank. There have been some scuffles in the last few minutes. Some of the demonstrators have been clashing with the police. No large-scale violence but pushing and shoving.
Following Obama's bilateral with Russian President Dmitry Medvedev, they have announced Washington and Moscow will pursue an arms deal cutting nuclear warheads below levels agreed in 2002.
Commander Simon O'Brien from the Metropolitan Police's Gold Command centre says the 3-4,000 people now outside the Bank of England did not tell the police their plans, making decisions about policing levels "very difficult".
1308BBC diplomatic correspondent Jonathan Marcus says:
The world that emerges from this crisis is going to be very different because foreign policy is changed by crisis. There are many people who argue that the impact of this financial crisis is probably going to be greater than the 9/11 attacks in Washington and New York.
Daniel James, Norwich, UK, says:
Why are the BBC talking about the G20 protestors as if they are a bunch of escaped convicts baying for financial blood? My Dad is protesting after finding that his pension is 60% lower than it was 12 months ago. He has worked all his life as a newspaper journalist.
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1258 The BBC's Mark Georgiou texts:
The crowd outside the Bank of England is getting increasingly tense. The police line in Threadneedle street is becoming the focus of loud attention.
Scotland Yard says the number of people arrested now stands at 11.
1252 BBC producer Dominic Hurst texts:
Protesters are penned into the square outside the Bank of England. A police officer said "we've been told not to let anyone out". The [police] tactics are like the Mayday protest in London's Oxford Street some years ago.
We should point out the G20 summit proper gets under way tomorrow. It lasts four-and-a-half hours. Even given all the pre-G20 legwork by the summit sherpas, it doesn't seem a lot of time to save the world.
The BBC's Mark Georgiou texts:
Billy brag. Singing to protestors outside bank.
City workers have been leaning out of windows to wave £10 notes at G20 protesters on the streets below, the Press Association reports. Demonstrators responded with jeers and shouts, their reporter says.
1220BBC's Dominic Casciani texts:
About two dozen black-clad men have charged police lines on Cornhill at Bank. There were minor skirmishes but the group sprinted away. Otherwise calm. A few minutes ago it got noisier when someone popped a head over the balcony of the governor of the Bank of England's office.
The BBC's Nick Robinson blogs:
The prime minister's always blamed America for this economic crisis. The French and the Germans have blamed Britain and America. "Who's right?" I asked them at the news conference. Their answers were instructive.
Read Nick Robinson's blog
1213BBC's Joe Lynam in Westminster texts:
If you thought any trouble would come from protesters during G20, think again. Scuffles broke out in Downing St between press photographers trying to get the best shot when Obama arrived to meet Brown. The police even had to intervene to prevent the situation getting uglier!
The BBC's Robert Peston blogs:
There's unlikely to be a return to business as usual in the global economy unless and until there's confidence that the banking system has been fixed and reformed.
Read Peston's Picks
Rob Higgins, England, says:
My family riding school business is under threat. I haven't invested in dodgy derivatives, I don't have a golden parachute, I don't have a pension, I can't get loans and will have to lay off employees. And all I hear is unbelievable tosh from Gordon Brown.
Have your say
Scotland Yard says eight people have been arrested after being found in possession of police uniforms. They were thought to be travelling in the armoured vehicle stopped earlier. Police estimate there are about 3,000 protestors in the City of London.
More than 10,000 police officers are involved in this security operation, which has been dubbed - perhaps with questionable judgment - Glencoe, also the name of a 17th century massacre.
1202 BBC producer Dominic Hurst texts:
Crowds are chanting "one solution revolution" and "climate, justice, peace" outside the Bank of England. Among them are groups of masked protesters from other European countries. Noisy but peaceful.
The BBC's Justin Webb blogs:
Nothing as glamorous as this has happened in London since William the Conqueror arrived, amid some controversy.
Read Justin Webb's blog
Anon, Canary Wharf, London says:
We've been given permission to not wear a suit today, some colleagues have taken that option but I'm wearing my suit and for the majority of people it's business as usual.
Have your say
Protesters at the Bank of England are getting louder, some are chanting: "Revolution". They are calling for the bankers and Gordon Brown to be put on a bonfire.
Optimist, Belgium, says:
I dare to hope that some good can come of this. There are huge problems to overcome and politicians are far from perfect. The tide is turning towards more honesty and equality. Let's give them a chance and not shout them down before the summit starts.
Have your say
1148 The BBC's Dominic Hurst texts:
Noisy crowd on move from Liverpool St. Peaceful. Police marshalling the line.
The BBC's Nick Robinson says:
The leaders here understand the need to be seen to stand together but they're here too, as of course they should be, to fight their own countries' corner.
Read Nick Robinson's blog
China and France have made up, after President Sarkozy met the Dalai Lama last year. The Chinese foreign ministry announcement came shortly before Mr Sarkozy was to meet President Hu Jintao in London.
China and France resume contacts
More protesters are converging on the Bank of England. Organisers say they are protesting against war, climate chaos and financial crimes. Some of the crowd, surrounded by journalists and photographers, are chanting "storm the banks".
Steve L, England, says:
The hysteria that's been created around the so-called rioters is totally pathetic. I work for a Japanese bank in the heart of the city. We have been targeted on their ridiculous map of companies. I have not dressed down today and I will not be intimidated by soap-dodging protestors.
Have your say
1125 BBC roving reporter Dominic Casciani in the City of London says:
Police are now allowing the first co-ordinated groups of protesters to move through back streets in the City towards the Bank of England. The protesters are carrying one of the "Four Horseman of the Apocalypse", part of the "Financial Fools' Day" rally.
Peter Lane, Bridgend, Wales, on his way to London, says:
I was laid off in December and have lost all my money and my house. I'm protesting about the government's management of the economy. The next generation will be deeply in debt.
Have your say
1115 BBC roving reporter Dominic Casciani in the City of London says:
A large number of protesters who assembled at Liverpool Street station have been told by the police that they will not be allowed to march onto Bishopsgate - one of the main routes through the City.
The US president's information pack for his trip to Europe describes the UK, under geography, as "slightly smaller than Oregon" (!).
Obama has now left Downing Street for his bilaterals.
Those helicopters above the Bank of England are not, so far as we're aware, for hurling money out of in a last-ditch stimulus effort.
Obama says he also loves the Queen, praises her decency and civility, and that Mrs Obama has been giving much thought to her meeting with her British monarch later.
Obama praises extraordinary affinity and kinship with British people, we owe so much to the UK and it is a special place, he says. But he refuses to get drawn into supporting England for tonight's World Cup clash against Ukraine!
1101BBC producer James Harrod texts
: Police helicopters circling above Bank of England. About 150 protestors gathered, nearly as many camera crews and journalists.
Brown says the worldwide fiscal stimulus - the amount of money governments are spending to try to boost their economies - now totals $2 trillion. It's the biggest fiscal boost the world economy has ever known, he says.
Obama says the media has "vastly overstated" any conflict between countries on how to tackle the global economic crisis. Almost every G20 country has engaged in its own fiscal stimulus he says, any differences on the issue are just "arguing at the margins".
Police in London have stopped a group of demonstrators in an armoured vehicle. They are now questioning about a dozen protesters.
Shawn, Yokohama, Japan says:
It's become more and more apparent (read: obvious) that the worlds central bankers run the worlds largest economies, and not the leaders of those nations. This is nothing more than public relations.
Have your say
Obama stresses the importance of this week's summit on saving and creating jobs. He warns however that the problem will not be solved in the next few days, "but we can make progress", he says.
Obama says US certainly has some accountability for the global recession. But he says he's less interested in identifying blame than fixing the problem and that in the US, they've taken aggressive steps to repair the economy.
Obama says we've passed through an era of profound irresponsibility and can't afford to go back to bubbles that go bust.
Obama says history shows that when nations fail to co-operate the price for our people is great. That is the lesson of the Great Depression. We must reject protectionism.
Gordon Brown sounded confident about the outcome of the summit, despite reports of splits between the nations. The world does want to come together, he says. He tried to reassure that the consensus will deliver "for people everywhere" creating new jobs.
Victor Baatweng, Francistown, Botswana says:
I believe we are the most affected continent though it's indirect. G20 countries should not just summit and end it there, we need them to implement the agreed policies as soon as they leave London.
Have your say
Brown begins his press conference full of praise for Obama. You have given renewed hope to all citizens in all parts of the world, he says. I congratulate you on your dynamism and energy.
1016BBC reporter Ben Geoghegan in Whitehall:
A handful of on-lookers - perhaps 50 - have turned up to catch a glimpse of the Obamas. There are almost as many police officers. Whitehall is lined with barriers but it looks as though people have decided to stay away from the area, perhaps because of the planned protests.
First ladies Sarah Brown and Michelle Obama tucked into sponge cake and drank tea with members of staff at Charing Cross Hospital. Mrs Obama says the first family will have a bee hive on the White House lawn.
Good point Lewis (below) about the smoke-filled room, because foreign dignitaries at the G20 will be exempt from the UK smoking ban. Does this leave you fuming, reader?
Lewis R Lowden, MI, USA says:
The G20 has a public face but is run from behind a closed door, smoked filled room, where-in the welfare of the general public does not have a seat. It's like asking the fox & ferret to make the rules protecting the chicken coop.
Have your say
Nicole, Limoux, France says:
We all need hope and this summit may give that. But the leaders in the summit need to remember what is "important" and stick to the agenda. That should exclude ego boosting.
Have your say
0952Jeff McCallister from Time magazine tells the BBC:
[Obama's] a rock star, he has a gorgeous wife, he is charismatic, young and vital. It's echoes of the Kennedys in early 1961. It's hard for me to imagine even if he doesn't fix the world economy in a day that this is going to go badly for him in political terms in the US or elsewhere.
0949BBC roving reporter Dominic Casciani outside the Bank of England says:
The policing is relaxed but visible. The square has been largely sealed off with crowd control barriers but about 50 protesters on bicycles have made their way through and set up a little sound system.
Sarah Brown and Michelle Obama are at Charing Cross Hospital to visit cancer patients. No comment, despite lots of "Are you happy to be here, Michelle?" shouts from waiting reporters.
0935Kevin Smith from protest group Climate Action
is on London Bridge, one of the key routes into London's financial district. He says: This model of constant economic growth isn't going to deal with the problem of climate change, it's actually going to make things worse.
David Foot, England, says:
Too much money has been spent over the last 30 years or so, until the experts take that on board no amount of talking will fix it. It is possible they may make improvements in the short term but this spending culture we have enjoyed must stop.
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0916BBC political editor Nick Robinson says:
It almost appears any deal will do. Gordon Brown believes it is vital the markets and public see G20 unity, what he describes as getting the oxygen of confidence into the system.
We'll also be following Angela Merkel and Nicolas Sarkozy as they hold their own press conference at 1630 UK time, to outline what they want from G20.
0857BBC diplomatic correspondent James Robbins says:
President Sarkozy is unlikely to follow through on his threat to walk out of the summit if he doesn't get his way. It was a theatrical move so he can go home and say they listened to what we the French had to say.
France threatens G20 walkout
Much drooling over Obama's Cadillac One, aka The Beast. It has bullet-proof windows, 5in armour designed to brush off a chemical attack and on-board supplies of Obama's blood type. Eat your heart out MTV's Pimp My Ride!
President Obama's security bubble
A member of London's "Whitechapel Anarchist Group" tells BBC Radio Five Live why he is protesting: "Why is it that people are worth a £600,000-a-year pension and we've got old people dying of hypothermia because they can't put money in their meters?"
If you happened to catch the three-point turn by Obama's Cadillac - the car that thinks it's a tank - outside Downing Street just now, either his chauffeur is under the influence or that thing is as difficult to manoeuvre as an airliner.
The G20 spouses, as the leaders' other halves are known, can look forward to Welsh lamb, Jersey Royal new potatoes and asparagus for dinner this evening. Michelle Obama will be seated between Harry Potter author JK Rowling and Olympic runner Dame Kelly Holmes, we are told.
Sarah Brown will host a First Wives Club later (not expected to include the husbands of Germany and Argentina's female leaders). The Saudi Arabian king's four wives are not making the journey either. With the French president's wife, Carla Bruni-Sarkozy, another no-show, Michelle Obama looks set to be Queen Bee.
Any ideas on what gift the Obamas might present to the Queen later? The prezzies they gave to the UK prime minister - Marine One toy helicopters and DVDs which don't even work in Britain - appeared to have been picked up from a car boot sale.
A glimpse of the first ladies as they pose for a photocall on the steps of Downing Street with their husbands. Looking reasonably informal, Sarah Brown is in a blue dress, Michelle Obama tops her outfit with a silver patterned cardigan.
Just a few minutes behind schedule, US President Barack Obama arrives in Downing Street for a meeting with Prime Minister Gordon Brown.
There already seems to be a split between the UK and US, on one side, who want more government spending to pep up the economy, and Germany and France, on the other, who are less ready to open their chequebooks. Let's just hope after this summit the chips in the White House canteen don't end up renamed as "Stimulus Fries".
President Felipe Calderon says Mexico is considering asking for a $40bn (£28bn) loan from the IMF, AP reports.
President Sarkozy tells Europe 1 radio he doesn't want to be associated with "false compromises", reports AFP. "As things stand at the moment, these projects [on the table] do not suit France or Germany," he says. Looks like Gordon Brown could have a bumpy ride.
BBC economics editor Stephanie Flanders says the International Monetary Fund (IMF) is expected to get several hundred billion more dollars to lend to countries in trouble after the summit. China is expected to contribute more money and in exchange will want a bigger say on how it's run.
Currently all quiet outside the Bank of England but a "Financial Fools' Day" protest is due to converge there later. All calm too outside the US ambassador's residence in Regents Park where the Obamas stayed last night. An anti-war demo is to be held at the US embassy in Grosvenor Square this afternoon.
France and Germany are not yet happy with the pre-G20 draft statement, President Nicolas Sarkozy has just warned, reports France's AFP news agency.
Lots of bilaterals today, including a Brown and Obama news conference this morning; Obama will later have a face-to-face with the presidents of Russia and China. The US president and wife Michelle will then meet the Queen as G20 leaders attend a Buckingham Palace reception, followed by a dinner at No 10.
For two days the eyes of the world are on London. The city has battened down the hatches for a huge security lockdown as world leaders, and demonstrators, gather. We'll be following every diplomatic pas de deux and protesters' placard.
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