The French say that the Tour de France is decided in 23 days in July, but this year the destiny of the leader’s yellow jersey has increasingly revolved around what Michael Rasmussen was doing during the 22 days in June when the Tour leader’s whereabouts were unknown to his national federation and the International Cycling Union (UCI).

This year’s Tour, blessed with a joyful opening weekend in South East England, had been expected to usher in a new era of transparency and renewal. Instead, nine years after the infamous Festina affair, the spirit of 1998 is alive and well.

Doubts over Rasmussen’s credibility have become crippling for this year’s race and yesterday the ambience of scepticism and suspicion was emphasised when French customs police searched four team buses at an autoroute toll station as the peloton continued its way through the Pyrenees.

Team buses belonging to the Astana, Discovery Channel, CSC and Rabobank teams were searched on the A64 autoroute. Corinne Druey, the spokesperson for the Astana team led by Alexander Vinokourov, yesterday’s stage winner, said: “They searched the whole bus, they searched the riders’ personal effects.”

Druey said that the search took place on a parking lot just outside the town of St Gaudens. “They found some prescription medicines, but did not take anything from the bus,” she said. According to Druey, the team buses belonging to French teams were not searched. “The customs let them go,” she said.

Brian Nygaard, the spokesperson for the CSC team, said that the search took “about ten minutes”. “When the team is travelling in France, you have to provide an inventory of the products you carry with you,” Nygaard said. “That list has to be confirmed before you start the Tour. They saw the list and checked that it corresponded exactly to what we are carrying.”

Police raids on team vehicles and team hotels were a characteristic of the troubled 1998 Tour and the present sense of unease has been exacerbated by the controversy over Rasmussen, the race leader, who has missed four out-of-competition doping controls since March last year.

David Millar, of Great Britain, who served a two-year ban after admitting to doping, was highly critical of the Danish rider yesterday. “He started the race knowing what would happen but did nothing to rectify the situation and now we are all screwed and the Tour is in the s***,” Millar said. “He took no notice of warnings from the UCI, though he deserved to be punished. He has either been unprofessional or has used the system.”

Other than a Rasmussen victory, it is difficult to predict what will happen next in this year’s Tour, so replete has it been with inconsistent performances. At the finish in Val Louron, it was the turn of Vinokourov, the winner of Saturday’s time-trial, anonymous also-ran in Sunday’s first Pyrenean stage and all-conquering mountain climber again yesterday, despite racing with 15 stitches in each knee.

Vinokourov’s victory lifted him up the overall classification, but he is still almost half an hour behind Rasmussen. Despite a series of attacks from Alberto Contador, the Spaniard who is his closest rival, the Dane responded to each acceleration and comfortably maintained his overall lead. With only tomorrow’s mountain stage and the final individual time-trial on Saturday likely to test Rasmussen’s resolve, his success seems assured.

Today is a rest day and Rasmussen will hold a press conference. Last night, questioned about the continuing misgivings over his performances, he looked momentarily stunned but was then defiant. “It has always been my intention to win this race,” he said. “I have no intention of giving up now.”