A CROSSING linking Scotland with Northern Ireland is a "visionary idea" and as deliverable as high-speed rail, one of Ulster's leading politicians has claimed.

Sammy Wilson, the Northern Ireland Assembly's former finance minister and leading member of the DUP, compared the plans for either a bridge or tunnel from Galloway with the HS2 project and airport expansion in south east England.

Discussing the DUP's role in the outcome of Thursday's election, Mr Wilson said it was a long-term project which was part of the party's strategy on better connecting Northern Ireland with the rest of the UK.

Amid much derision of the project Mr Wilson said it would be solution to high-price ferries and the impact of the weather on travel between Northern Ireland and the UK.

But leading engineers with experience of infrastructure projects in both Scotland and Northern Ireland have dismissed the idea is either unworkable or unlikely to have any economic viability.

Meanwhile, on south of Scotland MSP has described any crossing as "a miracle project" from "the land of dreams".

Mr Wilson, MP for East Antrim, home to the port of Larne, a major link between Ireland and Scotland, was discussing the link in an interview on his party's chances of becoming a coalition partner in the event of a hung parliament and the proposals they would push for.

In its 2015 election manifesto the party, Northern Ireland's largest and currently with eight MPs, wants a "feasibility study into a tunnel or enclosed bridge across the North Channel from Larne to the Scottish coastline".

The nearest Scottish town to Larne is Portpatrick, around 25 miles across the North Channel.

But any crossing would face Beaufort's Dyke, one of the deepest sea trenches in UK waters at 300 metres and the largest offshore dump site for conventional and chemical munitions after the Second World War.

The Dyke has always been the main logistical problem for such proposals, which have been floated since the Nineteenth Century.

But Mr Wilson said: "Manifestos have to be about some visionary ideas and these tend to be longer term projects. You can't just decide to get out the shovels and spades and start digging the next day.

"This mirrors the Channel Tunnel which was met with much derision. If you look at the history of the Channel Tunnel it was 20 years in the planning.

"The Government is now going to spend £35billion of the HS2 scheme, a high speed rail link through England which got the same kind of derision."

He said a feasibility study would conclude which the better option would be and whether it would be a road or rail crossing.

But Ronnie Hunter, until recently the chairman of the Institute of Civil Engineers Scotland, disregarded the bridge notion, comparing it with the costs and logistics involved in the 2500 metre new crossing at the Forth and adding that long viaducts only worked in shallow waters.

Mr Hunter added: "The distance is not far off the Channel Tunnel but there isn't the soft rock, the chalk and sandstone. It would be a stretch but doable. The issue is the cost to the Treasury based on any cost benefit, not the political will. Who would underwrite such a project?"

South of Scotland Labour MSP Graeme Pearson echoed the engineering concerns. He said: "The logistics really puts this into the realm of fantasy project rather than just a challenge. It's stuff from the land of dreams."

He added: "I would be very surprised if this was number one on the list of demands for any incoming government requiring immediate attention."