Virgin Trains has been urged by MPs to give up its appeal over the loss of the West Coast Main Line franchise and to accept that it is lost.

Sir Richard Branson’s firm came under fire from some Conservatives during a debate about the future of the West Coast Main Line, with one accusing the business of “sour grapes”.

But MPs split largely on party lines, and Labour’s Shadow Transport Secretary Maria Eagle said there were doubts about whether the winning bid from rival train operator FirstGroup was viable.

Virgin has asked for a judicial review after the Department for Transport accepted FirstGroup’s bid to provide inter-city services on the line, including trains from Birmingham to London and Manchester, for the next 15 years.

FirstGroup offered £5.5 billion for the franchise while Virgin, which had run the franchise since 1997, offered £4.8 billion.

Sir Richard claims that FirstGroup will not be able to deliver what it had promised and might be forced to abandon the franchise but FirstGroup, which runs four other UK rail franchises, insists this is nonsense.

The Commons debate took place after 170,000 people signed an ePetition to Parliament backing Virgin’s position.

MP Mark Pawsey (Con Rugby) said: “I understand Virgin’s concern. In my business, from time to time we lost contracts, which was particularly frustrating when we were confident in a bid and had given exceptional customer service in recent years. It is appropriate and shrewd business for Virgin to encourage their satisfied customers to make representation through the petition.”

But he added: “I advise the Minister to please get on with the process. I call on Virgin to withdraw its application for a judicial review. A decision has been taken. Let us get on with it and ensure that we get the right service for rail users in our constituencies.”

Daniel Kawczynski (Con Shrewsbury and Atcham) said: “My first reaction when I heard about Virgin’s judicial review was frustration and concern, and I felt a little as though it was a case of sour grapes.

“Subsequently, I met representatives of FirstGroup, who stand by their figures unequivocally. I also met representatives of Virgin and held a meeting in the House of Commons that was attended by 40 colleagues, who came to interact with Virgin’s senior managers and directors.”

He urged the Government to work with train operators to develop a bidding process they could all accept, to avoid costly court battles in the future.

Marcus Jones (Con Nuneaton) said many of his constituents were “a little perplexed, to say the least, about the whole saga of the letting of the West Coast Main Line franchise.”

He said that the court would now have to decide whether Virgin’s application for judicial review was successful, but he added: “To take the franchise process first: Virgin Trains and others, particularly Opposition Members, contend that the tendering process was flawed. I have concerns and scepticism about that argument.”

Concerns about the bidding process were only expressed after Virgin lost, he said.

He added: “There are a few questions about why Virgin or any other party did not raise such a high profile campaign at the outset. Why did we receive letters and ice lollies – I am not sure whether they were connected to this or were part of the Olympics – from Virgin Group on the train platform only once the bid was lost and Virgin had come in second?”

Mr Jones added: “For my constituents, the winning bidder at this point, FirstGroup, notwithstanding the legal case, is on the face of it offering the taxpayer a better deal and far better services to Nuneaton, which is what my constituents are looking for.”

Jeremy Lefroy (Con Stafford) praised Virgin for improving services on the West Coast Main line while it ran the franchise.

But FirstGroup was now promising to offer the same service at a cheaper price, he said – and Ministers would have been criticised if they had stuck with Virgin.

“Questions would have been raised about why the Government, on behalf of taxpayers, have accepted £700 million less, at net present value, simply because they liked the service that Virgin delivers, when a competitor claimed that it would deliver an equal service.”

Labour’s Shadow Transport Secretary Maria Eagle backed Virgin, saying: “The fact is that many respected people across the industry are dubious about whether the bid that FirstGroup has succeeded with is viable.”