SCOTLAND is in line for a windfall of up to £10 billion as a result of the controversial High Speed 2 (HS2) rail project, it has been claimed, with campaigners calling for the cash to go towards revamping the country's rail network.

Experts said UK spending on the proposed link between London, Birmingham, Manchester and Leeds will lead to extra money being funnelled north of the Border.

This is because of the Barnett formula, which adjusts the amount of public spending allocated to Scotland to reflect changes down south.

Campaigners said the cash should be pumped into rail projects such as an extension of the Borders Railway down to Carlisle.

Bruce Williamson, of campaign group Railfuture, said there was a “very strong case” for this, but added: “Because Carlisle is in England, there would have to be some sort of joint funding for that.”

He said: “Scotland has done much better than England in reopening lines. It’s not just the Borders Railway, there are a few others. They have all exceeded expectations. So you’ve got the proof of concept, that if you build it they will come.

“And rail is a much more environmentally-friendly form of transport. With the climate crisis, we need to reduce our carbon emissions and rail is a very good way of doing that.”

Mr Williamson said the money should “ideally” be ringfenced for rail spending, "in the sense that the more the better, really.”

Scottish Conservative transport spokesman Jamie Greene also called for the cash to be used to upgrade rail services.

He said: “Whilst the final numbers are unclear, the Scottish budget will have a significant uplift as a result of the UK Government’s commitment to HS2.

“The SNP has presided over a failing franchise where commuters face daily misery on our railways

“Any monies that come north of the border should surely at least in part be used in bettering rail services in Scotland."

Boris Johnson announced he would push ahead with the HS2 rail link earlier this week, with the first phase set to connect London and Birmingham. A second phase will go to Manchester and Leeds.

The Prime Minister said it had been a “controversial and difficult decision”.

The move is expected to cut London to Birmingham travel times from one hour and 21 minutes to just 52 minutes.

However, MPs were told last year that it may be at least 2028 before the first phase is up and running.

Concerns have also been raised over the rising costs – with one independent estimate putting it as high as £106bn. This would be almost double the £56bn earmarked in 2015.

Professor Mark Barry, an expert in connectivity at Cardiff University, said the impact of such spending on Scotland could be “quite considerable over the next 20 years” because rail infrastructure is devolved.

He told the BBC’s Good Morning Scotland: “If it’s a £100bn project, for example, Scotland could be expected to receive maybe up to £10bn over 20 years.

“Wales, on the other hand – there is no devolution of rail funding and powers, there is no Barnett consequential at the moment, which means Wales would suffer a disbenefit from the project – [it] actually pays for it and gets no consequentials.

“So Scotland’s in a much better position than Wales actually, in respect of HS2.”

He said Scotland would have an opportunity to enhance connectivity between major cities and reopen old routes.

Prof Barry added: “I look on with envy, actually, at what Scotland has and what it can do with the powers it’s got and the funding it will get.

“In Wales, I’m actually getting quite angry at the way Westminster and Whitehall have systematically underfunded the Welsh rail network for 30 years.

“I agree with the need for more rail capacity across the UK, but HS2, in the way it’s been funded and the way Wales has not been funded – it’s a slap in the face.”

Professor Iain Docherty, of the Institute for Advanced Studies at Stirling University, told the BBC's Good Morning Scotland that the total amount of money available to Scotland as a result of HS2 “will probably be a little bit less” than £10bn.

He said UK Government figures indicated it will actually be around £6 to £7 billion.

He added: “What’s really important from the Scottish Government’s perspective is that they take that money and they do the best they can with it for the economy of Scotland."

The Scottish Government's draft Budget for 2020/21 includes plans to "publish an action plan to decarbonise Scotland’s railways by 2035", focusing on electrification and "supported by [the] development and testing of alternative technologies" such as hydrogen-powered trains.

It also contains proposals to develop infrastructure improvements on key routes including Aberdeen to Inverness, the Highland Main Line, the Far North Line and the West Highland Line, among other schemes.

A Scottish Government spokeswoman said: “We have no information on any funding coming to Scotland as a result of HS2.

"The HS2 announcement made clear that funding would be considered as part of the forthcoming Comprehensive Spending Review (CSR) later this year.

“There is a considerable range of costs and there are still a number of decisions to be taken on the scope and scale of precisely what will be delivered and over what timescale.

"It is therefore not possible to predict what the financial impact for Scotland might be.

“It will be for Scottish Ministers to decide on the allocation of any consequentials if these are confirmed at the forthcoming CSR.

"In order to unlock the full potential of HS2, it must be extended into the north of England and Scotland.”