Transport Secretary Michael Matheson also warned that a Scotland-Northern Ireland bridge/tunnel proposed by Prime Minister Boris Johnson – which could cost £40-50 billion – risked sucking money away from schools and hospitals as well as other transport schemes.
The plans are included in an interim report published today as part of the UK Government’s Union Connectivity Review to improve links between different parts of the UK.
UK Transport Secretary Grant Shapps said the UK Government would spend £20 million on “exploring the development of projects”, including upgrading the A75 between Gretna and Stranraer, and “significantly faster rail links from England to Scotland, including options to enhance the west coast main line”.
The review has angered the Scottish Government, which stressed projects such as the A75 were its responsibility, and on which it had already commissioned studies.
Mr Matheson told MSPs it was “bizarre” that Mr Shapps appeared to be unaware that the Scottish Government consideration of such improvements was already underway.
He described the UK Government’s review as a “very shallow process” which attracted only 100 responses compared to 2,500 people responding to Transport Scotland’s South West Scotland Transport Corridor Study, which included the A75.
Mr Matheson said Mr Shapps “wanted me to accept the A75 should be our key priority over and above any other road project in Scotland – the Rest and Be Thankful/A83, the A82, the A96, the A9, the A1.
"It had to be the A75.
"You can’t operate a system where you are being asked, or being tried to be told that that should be your key priority.
"It has to be balanced out across all the other competing demands, not just in Scotland but in the south west [of Scotland] – around rail investment, investment in the A77, in the A76, in active travel [walking, cycling and wheeling].
"All these have to be balanced out to make sure they reflect the feedback we receive during the consultation process.
"That’s the process that will determine our investment – not the Union Connectivity Review, which is very superficial in its engagement.”
Mr Matheson said Northern Ireland infrastructure minister Nichola Mallon agreed with him a Northern Ireland bridge or tunnel was “not a priority”.
He said: “The danger in trying to plough ahead with a project of this nature is it will just suck financial resource away from other infrastructure projects, not just transport, but also schools, hospitals, housing, because this has been given the priority.
"The bridge/tunnel is nothing more than a vanity project.
"It won’t happen in my lifetime.”
However, Scottish Secretary Alister Jack, whose Dumfries and Galloway constituency includes the A75, said: “Strengthening road, rail, air and sea links across the United Kingdom will boost the whole country’s economy.
"Better transport within Scotland and improving our connections with other parts of the UK is a key element of this work.
"This includes looking at improving the busy A75 and introducing significantly faster rail links between Scotland and England.
"It is right that the UK Government invests in major infrastructure projects in Scotland to boost the whole UK economy.”