You have to hand it to Boris Johnson. Sometimes we snigger at his remarks but most of us have to admit that he is unpredictable. Often when he makes a pronouncement the press have a field day and then all is forgotten until the next big story, which in many ways is a pity.

On a number of occasions last year he mooted the idea of a bridge joining Northern Ireland and Scotland. A bridge between Scotland and Northern Ireland: what would it be like?

Prime Minister Boris Johnson's call for a feasibility study on a potential bridge spanning the Irish Sea made many smile. True to form, Boris put an estimate on it. He's good with figures, that’s for sure, although not too many people agree with his estimates.  But it might not be as silly as it seems.

The plans would see a 28-mile bridge between Larne and Portpatrick in Scotland, though an alternative route was also being considered.

One of the main stumbling blocks for this plan is the existence of Beaufort’s Dyke, a deep depression between the coast of Wigtownshire and County Down which goes down to a depth of 1,000 feet, i.e. more than 300 feet deeper than the Irish Sea average and in which obsolete explosives as well as radioactive materials were dumped after World War 2.

In December, Johnson advised the nation to “Watch this space.”

However, the best course of action might well be to build a tunnel instead, according to the Institution of Civil Engineers (ICE).

They say they want to dig two high-speed rail tunnels under the Irish Sea to link the four countries of the UK together for the first time.

The tunnel itself would run from the west coast of England to the Isle of Man, 50 miles from the coast, and then a second tunnel would run from the Isle of Man to the east coast of Northern Ireland, some 30 miles westward.

The proposed Anglo-Irish tunnel – if built to the specifications mentioned above – would be over twice the length of this, becoming the longest undersea tunnel in the world.

Of course, the construction of a tunnel connecting Britain and Ireland has been mentioned since the nineteenth century.

In 1956 the MP for North Belfast, Mr Montgomery Hyde, proposed the formation of a committee to examine the construction of a tunnel in a Private Member’s Bill at Westminster. He reminded members that an effort had been made by James Pirrie to propose such a motion in 1899, but it ran out of time. Hyde proposed a tunnel mainly for rail traffic and only for road vehicles if possible.

He spent 40 minutes outlining its advantages. Echoing Jules Verne, he pronounced: “The dreams of yesterday are the realities of today.” Hyde gave the House a comprehensive history lesson on Irish Channel proposals. In particular he dealt with the proposals advanced in the 1880s by a distinguished engineer called James Barton, a native of Dundalk. He had been responsible for the construction of the Severn Canal.

Barton envisaged a tunnel running from Islandmagee in County Antrim to Portobello in Wigtowntownshire. It was to be in the shape of a dog’s hind leg to skirt Beaufort’s Dyke and had the advantage of being just 600 feet in depth and 25 miles in length. Barton's “dog-end route” was discussed at a large public meeting in Belfast hosted by the Lord Mayor in 1890 and in 1901 was the subject of the International Engineering Conference in Glasgow where scaled drawings and plans were examined.

Two years earlier the plan was enthusiastically received at a large meeting of parliamentary peers and members, both unionist and nationalist. However, changes in administration meant that  the financial considerations were never fully explored and the plans were eventually shelved.

Hyde’s presentation was not helped by the fact that the leader of the Northern Ireland Senate had dismissed the idea less than a year earlier. Hyde quoted positive reports from leading engineering firm, Mott, Hay & Anderson, acknowledged experts on tunnels who had been the consulting engineers on the recently completed Mersey Tunnel and who in Hyde’s opinion were more expert than NI Senate leader, Lord Glentoran. Hyde’s  motion was seconded not by a unionist but by Lance Mallalieu, Labour MP for Brigg in Lincolnshire.

Reflecting on Stormont’s opposition, Hugh Delargy, MP for Thurrock, said:

“What absolutely astonishes me is that his (Hyde’s)  enthusiasm has never been reflected in his own province. A couple of weeks ago the Ministry of Finance made the surprising decision to scrap nearly every railway line in the six counties. If this decision is implemented there will very shortly be only one rail link between the six counties and  the rest of Ireland – the line between Belfast and Dublin.

East Belfast MP Alan McKibben interjected to say there was a line between Belfast and Bangor and another one between Belfast and Derry. The farce continued. When Delargy said he was referring to links between the six counties and the rest of Ireland, he was informed by McKibben: “We call it Ulster, not Northern Ireland.”

Referring to Hyde’s criticism of the NI Senate, Delargy made a great plea for a breath of fresh air in the Northern Ireland Parliament. He said: "He surprises me by his simplicity and absurd optimism. It is more difficult to get a breath of fresh air into the Northern Irish Parliament than it would be to build a tunnel from here to New York.”

The Joint Parliamentary Secretary to the Ministry of Transport and Aviation, Mr Hugh Molston, replied to Mr Hyde’s motion. He congratulated Hyde on his presentation. He reminded the House that in February 1955  he had given fully the reasons why the Government “are not prepared to give encouragement to the project of a tunnel under the English Channel, indicating the advantages of sea and air travel over rail.”  He said he was surprised that Mr Hyde in his presentation did not once refer to the invention of the aeroplane.

However, given the number of positive points made and mindful of “so many things in operation today which as Mr Hyde pointed out, were ridiculed at the time they were first adumbrated, that we would be well to be chary of saying of anything that is impossible.”

Hyde agreed to withdraw his motion on the understanding that Molston would give some consideration to the points made. Virtually nothing has been heard of it since. Two years later Hyde was deselected in his absence as unionist representative for North Belfast.

I won't be travelling to England or Scotland by bridge or tunnel but I look forward to Boris’s comments now that he has left Scotland. His mentor, Winston Churchill, wrote an article in the Daily Mail in 1936 entitled “Why Not a Channel Tunnel?”
Britain and France agreed to build theirs in 1964. Work began in 1988 and it became operational in 1994. That kind of timetable gives Boris plenty of time to fantasise.