Boris Johnson has previously described the bridge as a “very interesting idea”, while Ireland’s premier Leo Varadkar has said it was “worth examining”.

Two routes have previously been considered- from Portpatrick to Larne or near Campbeltown to the Antrim coast.

The Portpatrick route would be more than 20 miles across the Irish Sea.

The prime minister’s spokesperson said: “The prime minister has said it would have some merit – as a result you would expect government to be looking into it. Work is under way by a range of government officials.”

There could be a considerable price tag attached to the building of the bridge, with some experts advising £15billion, but others believe £20billion would be closer to the final amount.