Hendy told the The Daily Telegraph: “If you look at the distance between Northern Ireland and Scotland it is actually no further than the Channel Tunnel.”
Experts will now investigate an alignment between Stranraer, Scotland, and Larne, Northern Ireland – dubbed the Galloway Route, a sea distance of around 27mi (43km). One of the obstacles to be overcome will be the 300m-deep Beaufort’s Dyke – a natural trench in the seabed. This would not only necessitate a deep tunnel but also require removal of the extensive munitions dumped there after the second world war.
Johnson has previously mooted the idea of a bridge between the two countries and a fixed link is seen as improving connectivity generally across the UK but especially to strengthen the Union. However, experts have warned that high winds could see a bridge closed for up to 100 days a year; in contrast, a tunnel would be unaffected by the weather.
One suggestion for the potential tunnel would be an Øresund-type fixed-link sequence comprising (from the Northern Ireland side) a bridge, artificial island and then a tunnel to Scotland.
It is possible that the final tunnel arrangement would be similar to that of the Channel Tunnel, comprising two tunnel tubes with a service tunnel in between, although immersed tube solutions have also been suggested.