JUBILANT Michel Barnier last night revealed the EU will use the Brexit withdrawal deal to try to trap Britain into a permanent customs union.

Brussels’ chief negotiator said the terms of a UK-wide backstop to the Irish border will form the “basis” for the future trade deal.

And he warned Theresa May she will have to agree to grant EU fishing vessels access to UK waters in return for tariff-free access to the Single Market.

The Frenchman made the remarks as he hailed the “crucial step” forward in the talks at a press conference in Brussels last night.

He said: “Our objective is to abolish customs duties and quotas for all goods based on what we’re proposing in the Withdrawal Agreement, a single customs territory.

“This agreement offers a basis for future negotiations and that is in our common interest.”

In a boost for the embattled PM he added that sealing a wide-reaching trade deal is “possible” within the 21-month transition period.

Mr Barnier insisted he was not “self-satisfied or smug” about reaching an agreement despite eurocrats roundly congratulating themselves on the breakthrough.

But the comments will infuriate Eurosceptics already furious over a leaked diplomatic note that emerged yesterday from Sabine Weyand, Mr Barnier’s deputy.

In it she told ambassadors that Britain had agreed to “level playing field” measures tying Britain to EU rules in areas such as state aid and environmental and workers’ rights protections during a so-called post-Brexit ‘backstop’ or customs fudge.

She also said that Britain would “have to swallow a link between access to products and fisheries in future agreements”.

EU Commission boss Jean-Claude Juncker last night immediately wrote to his Council counterpart, Donald Tusk, saying “decisive progress” had been achieved.

And Danish PM Lars Løkke Rasmussen said: “Green light! Relieved that the UK government has now approved the deal reached by our negotiators. This is decisive for all European citizens and businesses. Hopefully we’ll soon be able to shake hands on a solid agreement.”

Meanwhile EU Parliament Brexit chief Guy Verhofstadt added: “This deal is a milestone towards a credible and sustainable future relationship between the EU and the UK.”