Plaid Cymru will vote against the Brexit trade deal with the EU negotiated by the UK Government.
The party’s leader, Adam Price criticised the “entirely false choice” between no deal and the deal which has been struck.
It is expected to pass comfortably after Labour’s Westminster leader Keir Starmer has indicated that his party will fall into line with the Conservatives.
Mr Price accused Labour of “swallowing the Tory lie” by backing the UK Government.
The House of Commons will vote on the deal on Wednesday and the Senedd will discuss it after being recalled. However, the devolved legislature does not have the power to have an impact on what happens and can be ignored by Westminster.
Adam Price said: “The notion that the choice is between the Brexit deal and no deal is an entirely false choice. It is deeply disappointing to see Labour swallowing this Tory lie.
“This is a Tory hard Brexit which will destroy jobs in key sectors like manufacturing, paves the way for ripping up workers’ rights and environmental standards and undermines democratic devolution.
“No party that claims to stand up for Wales, or for working people, can do anything other than oppose this deal and the future it represents.
“Plaid Cymru has never voted against Wales’ economic interests and there is no way that’s about to change.
“What Wales really needs is a New Deal – a relationship with Westminster which would allow us to be a good neighbour rather than a badly-treated tenant.
“This means control over our economy, justice, welfare system and natural resources where decisions are made in the best interests of everyone who lives here – a truly independent Wales.”
Plaid Cymru Westminster Group Leader, Liz Saville Roberts MP added: “This is a Tory-Labour stitch-up like no other. The Tory Government has strung out negotiations to run down the clock intent on ramming their deal through Parliament, while Labour is content in complicity.
“This deal will pass, with any vote reduced to a shabby rubber-stamping exercise that makes a mockery of parliamentary democracy and sovereignty.
“Under these circumstances, Plaid Cymru will vote with our conscience. We have always opposed leaving without a deal, but there is no question that this is a bad deal for Wales.
“Within days, businesses will face significant new barriers to trade when our economy is already in crisis because of Covid-19.
“Farmers who sell their lamb to the EU will now face complex new paperwork and checks.
“Manufacturers, deeply intertwined with EU supply chains, will face growing costs and administrative barriers. People were promised that leaving the EU would cut red tape, but the Tories have instead opted to create even more.
“This deal will lock out our young people from opportunities granted as a right to other young Europeans. Instead of Erasmus, young people are promised another half-baked pie in the sky.
“Politicians who benefited the most from free movement are depriving younger generations of the same opportunities.
“That is a historically destructive decision that we must oppose. It is important that we register our concerns about this deal, so that at the very least, future generations will know that such a bad deal did not progress through Parliament unopposed.
“On Wednesday, Plaid Cymru will stand up for the interests of Wales and vote against this bad deal.”