John Swinney rejected an offer by Network Rail to salvage the Glasgow Airport Rail Link immediately after the project was cancelled last September, it has been revealed.

Politicians who have called for the re-instatement of the project described the disclosure as “astonishing”.

The rescue suggestion is thought to have come from Iain Coucher, chief executive of Network Rail, in a phone conversation with the Finance Secretary in the days after the cancellation of the rail link project.

The scheme would have seen a mile of track built from Paisley to the airport to give a direct rail link from Glasgow Central Station.

But when Mr Swinney announced on September 17 he was cancelling the plan because of increasing costs he was fiercely criticised by businesses and west Scotland Labour politicians.

A source close to ministers said: “John Swinney was approached by Network Rail around the time the Glasgow Airport Rail Link was cancelled with an offer to use its own borrowing powers to fund it.

“It was rejected because it was felt this would jeopardise funding for other projects that are being paid for by Network Rail borrowing.”

Those projects included a £1bn package of improvements to rail infrastructure in the Central Belt.

The disclosure reignited the controversy that followed the decision by Mr Swinney to cancel the £210million scheme.

Charlie Gordon, Labour’s transport spokesman, said: “This raises questions about John Swinney’s statement to the Parliament’s transport committee on November 3, in which he said he had explored using Network Rail funding.

“I will be asking the committee convener whether Mr Swinney was frank enough in his evidence.”

A Scottish Government spokeswoman said no proposal had been made to fund the proposed link through Network Rail’s Regulated Asset Base – a means of using track infrastructure as borrowing collateral.

“The Cabinet Secretary received no proposal from Network Rail to fund Garl. Regulated Asset Base funding was one of a range of alternative funding sources considered and subsequently discounted for the Garl project,” she said.

A Network Rail spokesman said: “Our senior team has regular dialogue with Scottish ministers, but it is not our practice to comment on the content of those discussions.”