An undersea tunnel between Northern Ireland and Scotland has been proposed by the UK government’s transport planners.
The Guardian reports that the High Speed Rail Group's plan aims at joining up the UK's rail networks to boost Brexit trade.
The plan also suggests standardising the width of railway tracks across the two islands of Ireland and Britain.
It is understood that Irish Rail has not been consulted on the proposal, while Stormont's Minister for Infrastructure, Nicola Mallon, has dismissed the idea as "nonsense".
The proposal been called the "Boris Burrow" in the British press, as it replaces a proposal for a bridge backed by the British prime minister last year.
Civil engineer Eoin Neylon said Boris Johnson's new proposal would likely face similar stumbling blocks as his previous one.
I still don’t think it’s going to be coming in with a price tag of anything approaching acceptability to the British taxpayer
“He’s going to run into very, very similar stumbling blocks when it comes to trying to go underground,” Mr Neylon said.
“If he is spending this kind of money, a tunnel would at least get away from the severe weather issues that would keep a bridge closed for up to 100 days of the year.
“However, I still don’t think it’s going to be coming in with a price tag of anything approaching acceptability to the British taxpayer.”
Mr Neylon continued: “You’d do an awful lot more for the people of the six counties with 20 billion than you would by giving them a tunnel...
“God knows how feasible the actual operation of that as a proper trade route would even be.”