Scotland's Brexit minister Michael Russell has urged MSPs from all political parties to unite and back staying in the European single market.
Russell's call came in answer to an urgent question at Holyrood on the back of the last minute collapse of a deal between the UK and the European Union.
A proposal by the UK Government would have allowed Northern Ireland to maintain the same trade regulations as the Republic of Ireland.
The agreement was vetoed by Democratic Unionist Party (DUP) leader Arlene Foster, who said Northern Ireland must have the same Brexit deal as the rest of the UK.
On Tuesday, Scottish Conservative leader Ruth Davidson also rejected the suggestion and said "if regulatory alignment in a number of specific areas is the requirement for a frictionless [Irish] border, then the Prime Minister should conclude this must be on a UK-wide basis".
Russell told MSPs: "If this Chamber were to speak with one voice on membership of the single market and the customs union, I think it would be very effective indeed.
"Single market membership for the whole of the UK would be the way out of this incredible mess that has been created by Theresa May and I urge it on every member in this Chamber."
The UK Government maintains it will not join either the single market or the customs union after withdrawing from the EU.
Under questioning in the Commons, UK Brexit secretary David Davis said: "The suggestion that we might depart the European Union but leave one part of the United Kingdom behind, still inside the single market and customs union - that is emphatically not something that the UK Government is considering.
"So when the First Minister of Wales complains about it, or the First Minister of Scotland says it's a reason to start banging the tattered drum of independence, or the Mayor of London says it justifies a hard border around the M25 - I say they're making a foolish mistake.
"No UK Government would allow such a thing, let alone a Conservative and Unionist one."