The Tories have been accused of carrying out another "great train robbery" in Scotland over plans to deliver a real-terms cut to Scotland's railways.

SNP MP Alan Brown of Kilmarnock and Loudoun criticised Westminster for "ripping up" a long-standing funding agreement for Scotland's rail budget, amid claims there will be a £600 million shortfall over the five years from 2019/20.

But Tory transport minister Chris Grayling told the SNP they "can't have their cake and eat it".

Grayling said Brown's remarks represented an "historic moment" in the Commons, with the SNP opposing a funding allocation which uses the Barnett formula. The formula is used by the Treasury to calculate funding given to England, Wales, Scotland and Northern Ireland.

The Treasury has said the Scottish Government will receive more than £3.6 billion over the five-year period - an increase of £600 million on the previous period. The Scottish Government argues this is a "real terms cut" and that it needs £4.2 billion.

Speaking in the Commons, Brown said: "Mr Speaker, you may not be aware but last week there was another great train robbery when £600 million was removed from Scotland's rail budget due to the Tories ripping up a long-standing funding formula.

"So for the sake of Scottish rail users, will the Secretary of State get together with the Treasury and give Scotland the correct funding?"

Mr Grayling replied: "Well, this is an historic moment because this is the Scottish National Party opposing a funding allocation using the Barnett formula.

"Now I was under the impression they regarded the Barnett formula as sacrosanct, however, when the UK Government uses the Barnett formula, they complain.

"They can't have their cake and eat it."

Last week, Scotland's transport minister Humza Yousaf wrote to all opposition parties at Holyrood and called on them to unite against the cut.

Describing Scottish ministers' financial demands as "reasonable", he said: "The UK Government has departed from our agreed funding formula leaving Scotland's railways £600m short.

"This will undoubtedly impact upon our ability to enhance Scotland's rail network.

"It is of critical importance to Scotland's communities and businesses that we secure a fair financial settlement, which enables the Scottish rail industry to plan for the future with certainty.

"I am writing to political parties across the chamber to seek their support in calling for fair funding for our railways, I hope they will join with me in standing up for Scotland's rail network.

"I would urge the UK Government to begin serious and detailed dialogue with us on this issue as a matter of urgency."