The railway link is seen as vital to the Waverley line plan

Lib Dem MSP Jeremy Purvis has raised fears it could affect the business case for the Tweedbank to Edinburgh route.

He said the link to the airport was vital to reopening the Borders line.

SNP MSP Christine Grahame said her party objected to the route being suggested to the airport rather than the principle of the rail link itself.

Work is already under way preparing for the �155m reopening of the Waverley line, while MSPs gave their approval to the airport link plan earlier this year.

As far as I'm concerned the threat to the Borders line is if this particular �750m link were to press ahead Christine Grahame MSP

Mr Purvis is concerned, however, that the views of Holyrood's new SNP administration might have an impact on the Waverley line scheme.

He warned that the SNP's opposition to the airport link plan might lead to the dilution of the scheme in the Borders or, ultimately, contribute to its total failure.

However, his SNP counterpart Ms Grahame insisted that the opposite was the case.

Route opposition

"What the SNP is opposed to is that particular railway link - not a link between Edinburgh and the airport, but the route that particular line is taking," she said.

"The bill for that line is at least �750m and rising.

"As far as I'm concerned the threat to the Borders line is if this particular �750m link were to press ahead."

She said it would be possible to build a rail link to Edinburgh Airport which was much cheaper.