The National Audit Office has been asked to investigate the Government's decision to push forward a new bypass near the Silverstone race track in time for this year's British Grand Prix, against the advice of civil servants.
Pressure is growing on Tony Blair to give details of the "commitment" he made to the FIA, Formula One's governing body, to improve roads around the Northamptonshire circuit.
It is not the first time the Government's links with Formula One motor racing have caused a furore. In 1997, the vice-president of the FIA, Bernie Ecclestone, withdrew a £1m donation to the Labour Party after it emerged that the Government had canvassed for the sport to be exempted from a Europe-wide ban on tobacco advertising.
The Independent revealed yesterday that, in return for a pledge from the sport's governors that they would not pursue threats to scrap the race, Mr Blair had promised that problems with traffic would be sorted out in time for this year's race. Stephen Byers, the former Transport Secretary, authorised an extra £8m payment to accelerate the delayed road-building scheme.
Yesterday, the Government admitted its decision to award the £8m for the bypass was "political". The link was built on time and opened for the Grand Prix but closed afterwards so the entire bypass could be completed.
Mr Byers authorised the extra cash even though Sir Richard Mottram, then the most senior civil servant in his department, had warned it was not value for money and was not justified "on transport policy grounds".
Sir Richard was acting as his department's accounting officer charged with obtaining good value in line with Treasury rules. Such advice is rarely ignored and ministers have chosen not to heed it only 14 times since 1997.
Edward Davey, the Liberal Democrat Treasury spokesman, has written to Mr Blair demanding details of his involvement and asking whether he had put pressure on Mr Byers to approve the "unusual" payment.
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