Geldof sets protest in train, courtesy of his old pal Branson

Paul Vallely joins a mixed bag of activists on track for the G8 Summit in Edinburgh

The two men have come a long way since. Branson is now the boss of not just Virgin Trains, which dished out complimentary train tickets to activists, but also of Virgin Airlines, which had flown in, free, activists from the United States to lobby the G8 in Gleneagles.

Geldof, after the Live8 concerts which were watched by 3.8 billion people at their highest point, was on his way to Edinburgh claiming he had the biggest mandate for change assembled in history.

The train certainly bore out the variety of Geldof's new-claimed constituency, even if not its size; far from every seat was taken. Among the passengers were celebrities including the Hollywood actors Tim Robbins and Susan Sarandon and a smattering of film-makers and musicians. The demonstrators on board were drawn from 54 countries and included one activist who had spent three days travelling from Mali.

The rest of the passengers ranged from seasoned campaigners to those for whom the train was taking them on their first foray into activist politics. Among the most committed were the Greg and Sue Hall and their children Kate, 11, and Sebastian, nine. They were among the handful of intrepid yachtsmen who set out, at Geldof's instigation, across the Channel at the weekend to pick up French demonstrators after the Paris Live8 concert.

It took 16 hours for their 41ft steel-hulled ketch to reach Cherbourg in the face of a force 6 south-westerly on Saturday. And when they arrived they found no French demonstrators to collect. "The bad weather had meant that there had been an announcement at the Paris Live8 concert that coastguards were recommending no one to go to the coast," said Sue, 41, an NHS researcher So it was a bit of a flop? "Not at all," said Greg. "We rose to the challenge. We feel proud of what we've done." And it raised the profile of Africa for the children."

Kate was drawing a map of Africa as Geldof made a progress down the train and arrived at their table. A fly-on-the-wall documentary film-maker who specialises in faux-naïve questions was following the campaigner. "So why are you going to Edinburgh?" he asked.

"To make poverty history," she said, staring into his video camera.

"And how will going to Scotland do that?"

"It will put pressure on the leaders of the world's wealthiest governments," said the 11-year-old, unblinkingly on message. "A child dies in Africa every three seconds," added her little brother, without looking up from his Game Boy.

"We've brought our naval flags with us to spell out a message," Greg told Geldof. But it will not be England Expects so much as The World Expects, to judge by the multinational mix of passengers on the train.

What they had in common - even the tiro protesters - was a surprisingly detailed grasp of the policy issues before the G8. "It's the first time we've done anything like this," said Dave Coventry, 47, with his wife Lorraine. "But the children have left home now and we thought, 'Why not?' Freeing trade is the big issue, although that's inextricably linked to debt and aid."

He had briefed himself, he said, online. "The internet has made a huge difference. And action on climate change is all part of the same picture, though China and India should have been included in Kyoto. And then there's the big concert at Murrayfield tomorrow."

The internet had helped there too, telling him that the Proclaimers, Sugababes, Annie Lennox, the Thrills, Youssou N'Dour Ronan Keating, Texas, Snow Patrol, Travis, the Corrs and James Brown would be on stage. The mix of pop and politics continues to be a potent business.