A DEBATE over whether to construct a bridge between Scotland and Northern Ireland has gathered pace after the Democratic Unionist Party pledged their support for such a crossing.

Senior figures within the Ulster party seized on a suggestion by Professor Alan Dunlop, from the school of architecture at Liverpool University, who said a combined road and rail crossing could be erected between Portpatrick, in Dumfries and Galloway, and Larne in Northern Ireland.

It came after the Foreign Secretary Boris Johnson raised the prospect of a bridge over the English Channel last week. The Conservative government have a confidence and supply deal with the DUP which has secured £1bn in extra funding for Northern Ireland in return for their support in Westminster.

The Herald:

According to The Times, the Boris Johnson, proposal has revived calls for a 25-mile bridge or tunnel between Portpatrick in Dumfries and Galloway and Larne in Co Antrim.

READ MORE: Link between Scotland and Ireland would be a 'bridge too far', say engineers

It is thought the cost of the project would hit £20 billion - ranking it among the biggest infrastructure projects in UK history.

The Times reported that the DUP included a demand for a feasibility study into building a bridge or tunnel in its manifesto for the 2015 general election, when it and other smaller parties hoped to hold the balance of power.

The link was proposed by Sammy Wilson, a senior DUP MP, and Simon Hamilton, a former minister for the party in the Stormont administration who is touted as a future leader.

A DUP spokeswoman said a bridge across the Irish Sea could “act as a catalyst for developing further links between the two islands”.

Mr Wilson, a member of the committee which co-ordinates the relationship between the Conservatives and the DUP, told the Belfast News Letter that a bridge would “have a major positive impact on both countries economically”. He added: “People used to think the Channel Tunnel was pie in the sky. This idea of a fixed crossing has been derided as nonsense for years, but it is entirely feasible from a technical point of view.”

His favoured route would link Portpatrick to Larne. He dismissed a shorter 12-mile crossing to the Mull of Kintyre on the grounds that road infrastructure was too poor. He argued that the lack of a fixed link over the Irish Sea had driven up ferry prices.

The Herald:

Engineers have previously cast doubt on the feasibility of a bridge or tunnel, citing the problem of Beaufort’s Dyke, a 30-mile long, two-mile wide, deep-sea trench off the Scottish coast that was used as a munitions dump after the Second World War. It was suggested yesterday, however, that the stretch of bridge above the dyke could float like an oil rig.

READ MORE: Boris Johnson plan for bridge over Channel greeted with scepticism

Earlier this week, The Herald reported how Gordon Masterton, past President of the Institution of Civil Engineers, believes that the funds needed to finance such a hugely ambitious project would be better spent on links with the rest of the UK and Europe rather than across the Irish Sea.

Proponents have envisaged a viaduct similar to the 5-mile Oresund which links Denmark and Sweden, using a mix of pylons and a tunnel.

However, Mr Masterton said that any similar structure between Scotland and Ireland would have to overcome substantial engineering challenges while major infrastructure work would also been needed before it would be of any use.

He said: "It's not a new idea. There have been various ideas for bridges or tunnels between Scotland and Ireland down the years, although none of them has been properly costed or studied in any great detail.

"A fixed link between the two countries is all well and good if there are benefits to be had, but no-one has explained what they could be in any great detail.

"I would have thought that a far more effective way to spend the funds you would need for the bridge would be to extend the HS2 high-speed railway into Scotland and improve links with the rest of the UK and further afield in Europe."

READ MORE: Link between Scotland and Ireland would be a 'bridge too far', say engineers

However, Mr Masterton said that any similar structure between Scotland and Ireland would have to overcome substantial engineering challenges while major infrastructure work would also been needed before it would be of any use.

He said: "It's not a new idea. There have been various ideas for bridges or tunnels between Scotland and Ireland down the years, although none of them has been properly costed or studied in any great detail.

"A fixed link between the two countries is all well and good if there are benefits to be had, but no-one has explained what they could be in any great detail.

"I would have thought that a far more effective way to spend the funds you would need for the bridge would be to extend the HS2 high-speed railway into Scotland and improve links with the rest of the UK and further afield in Europe."