MINISTERS have been accused of attempting to rewrite history over their "ridiculous" boasts about a planned high-speed bullet train service between Scotland's two largest cities.

Transport Scotland had said that a business case for developing a Glasgow to Edinburgh high-speed line was submitted in the spring of 2014, two years after Nicola Sturgeon claimed that a 140mph link could be up and running by 2024.

However, the government agency is now refusing to release the document despite describing it as a "key milestone" in its high speed rail project, claiming the business case is actually "unfinished or incomplete".

It said the project, which has received £750,000 of Scottish Government funds, was "inevitably dependant on the upon the HS2 network in the rest of the UK."

It clashes with claims made by the then Infrastructure Minister Ms Sturgeon in 2012.

At the time she said that Scotland would be "firing ahead" with its own scheme regardless of progress with the HS2 bullet train project in England.

The plan for Scotland's own independent high-speed bullet trains has since been quietly shelved, with the Scottish Government now admitting any project is indeed dependant on a cross-border link with England being identified.

Transport Scotland insists that its high speed rail project has not been dropped.

It admitted that the government has not held any meetings about the high speed Glasgow to Edinburgh rail plan over the past year due to a lack of work by HS2 in identifying a cross-border link. All work on it has been "temporarily paused".

The Scottish Liberal Democrats had attempted to obtain the business case using freedom of information laws and have since appealed the decision. Leader Willie Rennie said: "What the SNP Government want is to keep this hidden so people can’t see them rewriting history.

"They want people to forget that they made a ridiculous promise to have a bullet train up and running between Edinburgh and Glasgow before HS2 had even got as far as Birmingham, let alone Scotland. They have quite clearly scrapped those plans given they haven’t met on a single occasion to discuss them over the past year.

"But we all know the SNP’s attitude towards freedom of information. They’d much rather keep people in the dark but the public deserves to know about the business case behind the Edinburgh-Glasgow plans and what three-quarters of a million pounds of their money has been spent on."

It has been claimed that the link could cut journey times between Glasgow and Edinburgh to under 30 minutes.

But there appears no appetite to extend the HS2 project into Scotland, with the first phase of the project set to establish a link between London and Birmingham. A second phase, not due to be completed until 2033, will go only as far as Leeds and Manchester

Last year, HS2 Ltd said there was "no business case" for extending the line to Scotland.

A Transport Scotland spokesman said: "When the draft Edinburgh to Glasgow high speed rail study was submitted to Ministers for consideration in 2014, it made clear that its delivery is dependent upon the details of route options on the cross-border high speed rail line.

"The Broad Options study undertaken by HS2 Ltd, which identifies the preferred options for cross border routes, is now nearing completion and future work on the Edinburgh to Glasgow high speed rail link will be informed by its findings."