At first, he rode hesitantly, wobbling slightly, but as he became used to the bike he began to pedal more confidently, easing around the temporary circuit. The crowd of builders in their hard hats and fluorescent waistcoats roared their approval. "Boris, Boris."
"Oh no. He's on the bike," said one of Boris Johnson's advisors with the resigned tone of a man who had been waiting for something like this to happen. And so the Mayor of London became the second person ever to ride in the Olympic Velodrome. Minutes earlier, Sir Chris Hoy had christened an arena that is now roofed and well on the way to becoming a 6,000-capacity state-of-the-art facility, representing £100m of the more than £7bn being spent on creating modern sporting temples in place of crumbling warehouses, industrial decay and, generations earlier, marshland.
"It will look as if it is floating in the air," remarked John Armitt, chairman of the Olympic Delivery Authority, the body charged with building the site in east London, as he surveyed the velodrome.
One of the features of the London Olympics – five years down, two to go – has been the attention to detail. It is a rigorously efficient set-up, from its dealings with the media to painstakingly fitting 32,000 different pieces of wood that can each go into only one place in the roof of the Aquatics Centre, to installing underfloor heating in the velodrome so competitors can remain warmed up between events. This is precision management.
The events to celebrate – and there was an air of celebration around the Park yesterday – two years until opening night were similarly well- defined. But that was without taking into account the 'Boris factor'.
The day had begun with the opening of the first London 2012 shop in St Pancras station – £25 and Wenlock the mascot is yours – and as Boris began speaking, a call to board the 10.25 train to Paris all but drowned him out.
It was Paris that London beat to the right to host the Games. With Britain's embarrassing record of sporting construction – Picketts Lock and Wembley to the fore – there were obvious fears for what lay ahead. In 2005, I stood in the square in front of Stratford Station, watching on a large screen as Jacques Rogge uttered one word: "London". The square erupted. A few months later, I drove around what was earmarked as the Olympic Park and tried to work out if a particularly dusty bit of land on an island created by dark, sluggish canals was where the stadium was to be built.
Yesterday, standing in the middle of the stadium, it would have taken a cold heart not to have felt a pang of excitement about what lies two years down the line. "Amazing," said Andrew Willis, a 19-year-old swimmer and Olympic hopeful. "It gives you all the motivation you need – the chance to be back here." He gestured up at the empty stands, waiting for most of the 80,000 seats to be fitted. "It is impressive," said Mark Foster, a veteran of five Olympics.
Other seasoned Olympians reckoned it was as intimate – if a venue of this size can be intimate – as any they have seen. The rows of seats slide right down to the edge of the playing area and, although the stands do not appear as steep as at many football grounds, the distance from the centre of the field to the back of the stands is less than at Wembley.
Entering the stadium, at this stage of its gestation, for the first time, stirs a realisation of what is going to happen here and in the other venues around the Park. This is going to be, as everyone from builders to athletes to administrators repeatedly points out, a once-in-a-lifetime thing, albeit one that has been expensively acquired.
We journeyed around the site, meandering between copses of cranes, with Armitt pointing out the different venues. Here is the athletes village, in walking distance of all the Park venues, a novel feature at a Games; here is the River Lea, where a double-sided giant screen will float on the water so people can sprawl on the grassy banks and watch medals being won.
Michael Johnson struck a rare note of caution amid a sea of evangelistic optimism. First, he took part in the debut race in the stadium, on a temporary track against a group of schoolchildren. It was won by Monique, taking a little slice of history all for herself. "She's fast and she's 10," said Dylan Brown, another of the racers. "I'm only nine."
Johnson, multi-Olympic gold medallist, knows the unique pressures of competing in a home Games. He ran in Atlanta – successfully – and spoke of how testing it was to have that immense expectation riding on your shoulders. He had little time, he explained, to enjoy Atlanta – few, as Olympic legend has it, did anyway.
But did he think the London Games would be a success?
"You cannot know that until the fans walk away at the end," Johnson said. "Until then, there is no other way of knowing."
With the build ahead of schedule and the budget, for the time being at least, under control, what does he see as the biggest challenge still to overcome? "It will be how they deal with the unexpected because something will happen between now and the start."
The budget may yet face further paring come the government spending review in autumn. Johnson – the mayor, not the runner – issued thinly veiled warnings to his Tory colleagues across the river from his offices on the south bank of the Thames to keep their hands off, while Hugh Robertson, the Minister for Sport and the Olympics, offered reassurances that all would be all right for opening night.
The opening ceremony has to follow in the multiple footsteps of Beijing, and its chances of matching, let alone bettering, that one-party state spectacular are slim. But yesterday was a time to believe. "Sure, we can better Beijing," Foster said. "Why not?"
It was in Beijing that Johnson, then a newly arrived Mayor of London, introduced himself to the world. There is a possibility that, come London 2012, he will be confined to the stands. In May that year, he will stand for re-election – a race he must win if he is to stand in the middle of the Olympic Stadium on the evening of 27 July 2012 and welcome the world to, as he put it yesterday, "the greatest party on Earth in the greatest city on Earth."
Whether the opening ceremony will then feature Boris on a bike in some sort of Tebbit sketch remains to be seen, but Hoy, barring injury, will be there.
"The last time I was here," he said as he stood in the velodrome, "it was a hole in the ground." Hoy is among the athletes who have been consulted in the building of the venues. "The focus has been from the athlete's point of view. Everything has been addressed – even the toilets are only a 15-second walk away for the competitors. We never usually get looked after like that. "It's that attention to detail again, a detail that is promising so much in two years' time."
It started to rain as we walked over the main bridge, past the Aquatic Centre and into the stadium. The 70 athletes from Team 2012 snapped pictures of each other and, perhaps, dared to dream.
"Doing this, you get a sense of what it's going to be like," Hoy said. "It really gets the enthusiasm going. Two years to go – I can't wait."