The UK government is investigating the possibility of digging a tunnel between Scotland and Northern Ireland, the Scottish secretary has said.
Prime Minister Boris Johnson has previously raised the idea of a bridge being built across the Irish Sea.
But Alister Jack told MSPs this was a "euphemism" for a tunnel, saying "it would be less expensive to tunnel it".
Nicola Sturgeon had distanced herself from the bridge plan, saying there were "more important priorities" for funds.
The Scottish Greens said the idea was "pure fantasy, just like the Tory approach to Brexit".
