Skidding around corners at 45mph, Pat McQuaid's car was directly in front of the tete de la course riders.
It careered around the 1.1 mile course, taking in the Victoria Embankment, Big Ben, Nelson's column, and other London landmarks.
The crowds were a blur but clearly there were thousands of people lining the route. Some commentators have said there were 200 000 people watching the London stage, although Tour officials believe it was more like half this. In pre-Tour health and safety submissions, the estimate for the likely number of spectators was 100 000 and this number was probably just about exceeded.
Crowds for the Tour of Britain as a whole exceeded expectations, with many thousands on all stages, with only the Newport stage being lightly attended.
The initial safety fears from the peleton were quelled after the first day, said the race's technical director, Michael Bennett.
"Everybody was rusty, we haven't had a tour of this size in Britain for five years. After the first day everything was handled much better."
Robin Williamson, owner of the eponymous bike shop in Edinburgh, was the Tour of Britain's clapperboard-timer motorcycle driver and was in thick of all the Tour's action from the start. He said he was "staggered" by the number of spectators en route.
"It was amazing, there were so many people. Holme Moss was packed, Blackpool was really busy. A lot of the foreign technical people have been saying there were more crowds on the route than at longstanding tours such as the Tour of Germany. That's got to be good news for cycle sport in this country."