A Parliamentary select committee chairman today asked the Government to delay signing off the deal which will see Sir Richard Branson's train company lose its West Coast Main Line rail franchise.
Sir Richard dubbed the franchise system "insane" after the Department for Transport (DfT) last week announced that Virgin Trains has lost out to transport company FirstGroup in the battle to operate a new 13-year West Coast franchise from December 2012.
The final contract papers for the deal are expected to be signed by Transport Secretary Justine Greening next Tuesday.
Today, Louise Ellman, the chairman of the House of Commons Transport Committee, wrote to Ms Greening asking her to hold off signing the final contract.
In the letter, Mrs Ellman said the West Coast ruling raised "important issues about the basis on which decisions on major rail franchises are made".
She added that she wanted time to raise the matter with her committee colleagues and that she was proposing a possible public oral evidence session of the committee on the subject of West Coast on September 11.
Mrs Ellman also said in the letter that she expected committee members would want to ask about the West Coast franchise when Ms Greening gives evidence to the committee on the work of the transport department on September 12.
A DfT spokesman said: "Once a decision has been made it is in the public interest and the commercial interests of bidders for the identity of the winning bidder to be made known promptly.
"Our published processes and criteria do not provide for a role in a live procurement exercise for the transport committee, which has not requested any kind of dialogue on this issue before now.
"However, the Secretary of State is due to appear in front of the select committee in early September and will be happy to talk about the business of her department."
Virgin, which has operated the West Coast line since 1997 and has more than doubled annual passenger numbers over 15 years, has mounted an internet campaign to put pressure on the Government to reconsider the franchise award.
The campaign has attracted some celebrity names including double Olympic champion Mo Farah, The Apprentice presenter Lord Sugar and celebrity chef Jamie Oliver.
Today a FirstGroup spokesman said: "We appreciate that Sir Richard Branson is a high-profile celebrity with millions following him personally on social media. However, our business is transport - first and foremost.
"We are introducing major improvements to the InterCity West Coast franchise to enhance the customer experience, including improved wifi and catering, as well as additional services and more seats and reducing standard anytime fares by 15% on average.
"We have a long and proven track record in running rail services and will be delivering better value for taxpayers. We look forward to welcoming all customers to their new and improved service from December."
The franchise decision could be debated in the Commons after a petition calling for a rethink was signed by more than 100,000 people.
Having crossed the 100,000-signature threshold, an MP could ask the Commons Backbench Business Committee to allocate time for a debate and possible vote on the issue.
Liberal Democrat president Tim Farron, MP for Westmorland and Lonsdale, wrote on Twitter: "Now the @VirginTrains petition has reached over 100,000 I think we must debate the issue in Parliament."
The call for a rethink, submitted to the Government's e-petition website by Ross McKillop, said ministers "should look at more than the highest bidder - look what happened with G4S at London 2012".
It added: "I urge the Government to reconsider this decision or to seek public opinion in these franchise bids."