By Simon Austin
The Lions squad assembled on the Heathrow tarmac before heading south
The Lions have set off for South Africa with head coach Ian McGeechan warning they face the toughest challenge in their history.
"Airforce Scrum" left Heathrow at 1905 BST on Sunday and is due to land in Johannesburg at 0550 BST on Monday.
"South African rugby is in very good shape and they have stability in their coaching team," said McGeechan.
"We know how tough this tour is going to be. It is probably the toughest challenge the Lions have faced."
This is the 62-year-old's fifth Lions tour as a coach and his seventh in all, as he also represented them twice as a player.
In 1997 he famously led the side to a 2-1 series win over a strongly-fancied South African side.
Then, as now, the Boks were the reigning world champions, yet McGeechan argues they are a much stronger outfit now.
"That South Africa side was very good, make no mistake about it - I remember they beat Australia by 60 points after the Lions series," he told BBC Sport.
"But the game had only just gone professional in 1997 and the amount of work that they put into their side compared to now is chalk and cheese.
"This side is fitter, more settled and better prepared. It's a bigger challenge for us than in 97, make no mistake about it."
McGeechan said he had watched the Bulls, who are likely to provide the bulk of South Africa's Test side, beat the Crusaders 36-23 in the semi-finals of the Super 14 on Saturday and been "very impressed".
Yet the Scot was also extremely upbeat about the work his own players had put in during their training week at Pennyhill Park.
"The week has gone very well and the lads have been excellent," he said.
"We got straight down to the rugby on Tuesday, looking mainly at tactical and technical things, and have been training twice a day since then.
"It is as good as it has ever been on any of the Lions tours I've been involved in."
He was also heartened by the bonding the players - who are drawn from England, Ireland, Scotland and Wales - had done away from the pitch.
"The players seem very at ease in each other's company," he said. "Sometimes you don't get that initially on a Lions tour, but it is very important.
Ian McGeechan is under no illusion about the challenge ahead
"The Lions is such a unique thing and togetherness has to be a big part of it. You have to understand each other as people as well as rugby players."
After contesting the Heineken Cup final on Saturday, the Lions' Leicester and Leinster contingents joined up with the rest of the squad on Sunday.
And McGeechan admitted he was relieved that 2005 Lions skipper Brian O'Driscoll had suffered no ill-effects from a shoulder injury sustained in the Murrayfield match.
"I must admit I did have a second look when Brian went down, but he is fine," he said.
O'Driscoll, who led Leinster to a 19-16 win over the Tigers, said: "You get 'stingers' and that sort of thing in games - I've had a few of them."
This will be the Ireland captain's third Lions tour and he hopes to fare better than in 2001, when the Lions lost 2-1 in Australia, and 2005, when they were whitewashed in New Zealand.
"I am very motivated, and the goal is to try to win a Test series and to be a part of that," he said.
"It is not about being involved in the squad or touring South Africa and having a great time - it is about winning a Test series - that is the bottom line."
McGeechan confirmed that none of his Leinster players - Luke Fitzgerald, Jamie Heaslip and Rob Kearney - or those from Leicester - Harry Ellis and Tom Croft - would be considered for the opening tour game against a Royal XV in Rustenburg on Saturday.
Scotland prop Euan Murray, who featured in Northampton's European Challenge Cup victory over Bourgoin on Friday night, will also watch the game from the sidelines.