Labour has been urged to join a cross-party bid to keep the UK in the single market and customs union after Brexit.
The SNP, Liberal Democrats, Plaid Cymru and Greens have joined forces to back an amendment to the EU (Withdrawal) Bill when it returns to the Commons this week.
If passed, the move would stop ministers being able to use so-called Henry VIII powers to take Britain out of the single market and customs union.
The move follows a Brexit summit by the leaders of the four parties which Labour refused to attend.
SNP Westminster leader Ian Blackford said: "Time is running out to prevent the economic catastrophe of an extreme Tory Brexit.
"We know UK Government plans to drag Scotland and the UK out of the single market and customs union would destroy hundreds of thousands of jobs, and cause lasting damage to the incomes, livelihoods and living standards of millions of people across the country.
"With just 10 months to go before a deal is due between the UK and EU, sensible MPs of all parties must now unite to protect our vital place in the single market.
"Short of remaining in the EU - as Scotland voted for - retaining our single-market membership is by far the best compromise and the least-damaging option."
Liberal Democrat leader Sir Vince Cable said: "This amendment is a significant step in the fight against Brexit, demonstrating the increased willingness of parties to work together formally rather than just behind the scenes.
"Through the four leaders in the House of Commons, we are presenting a united front.
"We urge the leadership of a fifth opposition party, Labour, to join us so we can change course from the dangerous Brexit being pursued by the Conservatives."
Plaid Cymru Westminster leader Liz Saville-Roberts said: "We remain hopeful that the Labour Party will work with us and take the opportunity to defeat the Tories."
Green Party co-leader Caroline Lucas said: "What happens this year in Parliament will have huge and lasting repercussions for the country - which is why we're putting party differences aside and working alongside each other.
"We urge the Labour leadership to join us in backing this crucial amendment - and show that they too are willing to put the national interest first."
Labour's position is that it wants to negotiate a deal with the EU to retain the benefits of the single market but insists it is not a membership group that can be joined after Brexit.
A spokesman for the Department for Exiting the European Union said: "We respect the four freedoms of the EU and that is why, as we leave the EU, we are leaving the single market and customs union.
"The purpose of the Withdrawal Bill is to provide a functioning statute book on the day we leave the EU, not to pursue policy choices like this.
"The alternative is legal chaos that would harm the interests of everyone."
Meanwhile, former Ukip leader Nigel Farage has warned the Leave side need to regain the political initiative or Brexit could be scuppered.
He told The Observer: "The Remain side are making all the running. They have a majority in Parliament and unless we get ourselves organised we could lose the historic victory that was Brexit."