The new policy reiterates the tests the TUC set for the original deal, calls on parliament to reject any deal that does not meet these tests, and insists that any deal must be subject to proper democratic approval with the option of a public vote on the deal kept on the table.

The motion goes beyond previous TUC policy and reflects a shift in the trade union movement and across the country with growing unease at the possibility of a ‘no deal’ Brexit or a so-called ‘blind Brexit’ where the UK leaves the EU with no clear idea of what the future relationship will look like.

In a keynote address to TUC Congress Shakira Martin, the president of the National Union of Students, praised Prospect for helping to lead the debate within the union movement by passing a similar motion on Brexit at Prospect national conference in June.

Prospect senior deputy general secretary Sue Ferns said:

“Prospect members are at the frontline of Brexit and it is right that we are leading the debate within the union movement and across the country.

“The public must have a say on the terms of Brexit, just as unions bring any negotiated agreement back to our members for approval.

“We are only a few months away from leaving the EU and with no certainty from the government it is more important than ever that unions stand up for our members and campaign to put their interests front and centre in this process.”