In the days after the 7 July bombing three years ago, Londoners responded by declaring, in all sorts of ways, that they were "Not Scared". It doesn't look like that any more. A poll conducted to mark the anniversary of the bombings finds that Muslims have experienced a marked increase in hostility since the attacks. People feel threatened by Islam, and the more savage and cowardly among the population express their own corrupting fear in acts of sometimes very serious criminal bullying.

Shahid Malik, Britain's first Muslim MP, is in no doubt that Muslims are uniquely targeted. He warns that Muslims feel like "aliens in their own country" and like "the Jews of Europe". Noteworthy as his observations are, I can't subscribe to the idea that only Muslims are being singled out for hostile or resentful attention. It is sad enough that this one group feels it is being burdened with collective blame for the aberrant behaviour of a radical and nihilistic few. But Muslims are not the only group being tarred with guilt by association.

An extraordinary consensus is being reached in this country, personified by the warning this week from Mayor of London, Boris Johnson. The consensus is that young people are so fearsome that one should not intervene if one sees them fighting. Is it right, then, to be frightened of all young people, and right to allow that fear to overcome any finer instincts? Where does this dispensation lead?

One in four young people, we are told, carry knives, not because they are aggressive but because they are fearful of aggression. How can such pronouncements restore their confidence? They are being told, after all, that if they cannot defend themselves, then no adult should be expected to step in on their behalf. Should we do the same when we see a Muslim being intimidated or bullied? Or a Pole? Or a Somalian? Or any other human?

Johnson explains that his advice is all about personal risk. Already, though, we are seeing how prioritising personal risk above civic responsibility further damages the systems we have developed for our own protection. The Government has already drafted its emergency legislation, designed to avoid the catastrophe whereby the law lords' rejection of witness anonymity threatens no fewer than 600 criminal cases.

While so far it has been pointed out only that witness anonymity destroys the defendant's ability to cross-examine, the truth is that it also imposes grave restrictions on public access to criminal justice. The witnesses who testify anonymously in trials cannot speak either to the media or even to others in their own communities about what they know and what they have seen.

It is a problem, this inability to explain the background to frightening crimes, because everything is more frightening in the dark. There is such a hazy understanding of what there is to fear that the tendency is just to fear everybody, to be "on the safe side". One cannot excoriate people for being fearful. But it is important to remember that it a good thing, not a foolish thing, to try one's best not to succumb to fear. Thursday night, during a report about the unspeakable murder of two French students, a neighbour spoke to the cameras anonymously, for fear of reprisals. All he was saying was that he had heard an explosion. The collective imagination is running rampant when people believe that going on telly with such innocuous information places one at risk. The media are only too happy to cater to the delusion.

The political commentator Peter Oborne rightly suggests that mischievous stories in the media fuel Islamophobia. He is right in his assertion, but wrong, like Shahid Malik, in his suggestion that this sort of black propaganda is unique to Muslims. Asylum-seekers, of indiscriminate race or creed, have been treated in this way for years, and the legislature has responded harshly to that pressure. Eastern Europeans are treated similarly. And so are young people, who are endlessly subjected to "why, oh why" columns about their intractable insubordination.

I am no hero. But I regularly challenge my fellow citizens when they are indulging in behaviour that is recognised as undesirable. I've tackled loud boys on the bus, silent boys as they break into parking meters, grown men dropping lager cans, weird men yelling obscenities on the Tube, sinewy girls as they fail to dispose of their dogs' excrement, and lairy girls when they block stairwells. These encounters are not always pleasant, but more often than not, they are. More often than not people are embarrassed, or apologetic or fairly cheerful about being pulled up.

There have been terrible stories in the press recently about people who intervened in small cases of anti-social behaviour, and paid with their lives. Those cases, it is important to remember, are striking because they are so unusual. In response to the bad behaviour of young people, it is common to blame the parents. Yet parents, when no other adults are encouraged to uphold the values they wish to instil, are denied wider cultural support. Millions of us want public areas to be safe. Only a few want to own them themselves, as fiefdoms of fear. It's doing their job for them to cave in so eagerly to our disproportionate sense of personal threat.

* It's OK to be scared by Doctor Who, though. Or lately, simply in awe of him. Last week's episode, in which viewers were introduced to the idea that David Tennant may be out on his ear, was astounding. It's become normal for every media event to be hyped up. Even when such a course is officially avoided, it's usual for a citizen journalist to tip off the papers. The BBC's public-service status may be under threat. But at least it can still teach the Government a thing or two about how to avoid leaks.

Who's that lady in the dock, Dad?

Christie Brinkley, the supermodel who inspired one of her four former husbands, Billy Joel, to write "Uptown Girl", is in the throes of a stonkingly downtown divorce case. Loonily, she has opted to be heard in open court, because she wants her children to know "the truth".

She's says that her ex, an architect called Peter Cook, should not have custody of Joel's son Jack, whom he adopted, and the daughter the couple had together, Sailor Lee. Cook claims, on the other hand, that he should, because Brinkley employs nannies to look after them. One does have to wonder, however, why there is so little evidence of Cook straining to be a paternal presence in the household while the pair were still together.

Far from rushing home to wrest the children from the dreaded professional embrace, he instead embarked on an affair with an 18-year-old, with whom he had meetings in his office and also at the homes he shared with his wife.

What's particularly weird is that the children in question are not babies but are 10 and 13 years old. So really, you'd need nannies for them only if you happened to be doing something that you really didn't want them to see. Like fighting over them, say.

Shop till you drop (down drunk)

Another report has come out confirming that new licensing laws have not turned England and Wales into Italy and France. It has simply redistributed drink-related crime and injury so that it happens over a less concentrated period. How silly Labour was in making such high-flown claims for its policy.

Its idea was that 24-hour drinking would herald a continental café culture, and banish binge-drinking. But the establishments that genuinely offer a 24-hour service tend to be supermarkets and off-licences, which means only that after you have drunk the house dry, or been kicked out of the bar, you can restock instead of deciding that it's time to call it a night.

The Adam Smith Institute, which supported 24-hour drinking, quoted John Stuart Mill in the run-up to the 2005 shake-up. When he wrote On Liberty, Mill fulminated about how restricted licensing "not only exposes all to an inconvenience, because there are some by whom the facility would be abused, but is suited only to a state of society in which the labouring classes are avowedly treated as children". We have moved on since his day, and it has now been noted that it is children who tend to go searching for off-sales booze in the middle of the night.

The solution, says Labour, is to come down harder on places that sell alcohol to kids – upholding the law as well as just fiddling with it. And people say they've run out of ideas.

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