In a speech to a right-wing think tank, minister Steve Baker said the EU should be “wholly torn down”, before branding it an “obstacle” to world peace and “incompatible” with a free society.
Tory MPs warned Mr Baker’s appointment could now risk the UK’s ability to secure good Brexit terms, while Labour said it was “extraordinary” and raised a major question about the Prime Minister’s judgement.
The comments are likely to prove embarrassing for Ms May as she heads into meetings with European leaders this week, including Angela Merkel and Emmanuel Macron.
In the video Mr Baker tells a cheering audience: “I think Ukip and the Better Off Out campaign lack ambition. I think the European Union needs to be wholly torn down.”
Filmed at an event by The Libertarian Alliance in 2010, he goes on to argue that the EU has “succeeded in raising economic nationalism to a continental scale”.
The Wycombe MP, who played a lead role in the Leave campaign, adds: “It was meant to defeat economic nationalism, it is therefore a failure in its own terms.
“If we wish to devolve power to the lowest possible level, make it accountable and move on into a free society, then it’s clearly incompatible.
“What I want is free trade and peace among all the nations of Europe as well as the world and in my view the European Union is an obstacle to that.”
The cabinet and wider Tory party is split over the EU, with many MPs pushing a weakened Prime Minister for a more jobs-focussed approach to withdrawal, while Brexiteers are said to have threatened resignations if she changes tack.
Backbench Tories have also said they are working with other parties to try and soften the hardline approach to Brexit Ms May took into the election.
After seeing the video, one Conservative MP told The Independent: “It just reveals what the extreme Brexiteers have been about all along.
“It’s not enough to take the UK out of the EU. They want the entire thing to fall apart.
“How is it possible to negotiate a ‘deep and special relationship’ with the EU, when you have ministers who want the institutions they are negotiating with to disintegrate?”
Another MP said: “This is only going to further embitter relations. It doesn’t help our chances of getting a deal.”
Tory MP Anna Soubry said: "Now he's a minister he will be bound by collective responsibility and his views will no doubt be tempered by realism and maturity."
Shadow Brexit Secretary Keir Starmer, who has called for a more co-operative approach to Brexit, said: “there should be no place” for Mr Baker’s views at the Department for Exiting the European Union.
He added: “It is extraordinary that Theresa May has put such an extreme Brexiteer at the heart of the Government.
“This poses real questions about her judgement and the Government’s desire to build the collaborative, cooperative future partnership we need with the EU.”
Liberal Democrat Brexit spokesperson Tom Brake attacked Ms May for appointing a Brexit minister “dedicated to destroying the EU”.
The issue will hang over the Prime Minister as she meets German Chancellor Ms Merkel and French President Mr Macron at the G20 in Hamburg on Friday, whom she has both assured the UK wants a “deep and special relationship” with the EU.
On the same day Brexit Secretary David Davis is inviting jittery business leaders to Chevening in a bid to convince them discussions are in good hands and EU withdrawal will not damage their hope of future trade with the bloc.
A spokesman for Mr Baker said he now “supports the Government's position and that is why he was happy to take up a ministerial position.”
He was taken on in the post-election reshuffle as Ms May desperately attempted to shore up her position with MPs livid that she had botched the election campaign and lost her party’s majority.
He brought with him the backing of a large swathe of the Tory backbenches – he was chair of Conservatives for Britain, a 50-strong group of Tories who fought Leave, and then went on to run the European Research Group, a pro-Brexit backbench organisation.
The reshuffle which brought him in saw half the ministerial team at Dexeu replaced, with one sacked and another, George Bridges, walking out after it was claimed he became “convinced Brexit couldn’t work”.
Earlier this year, Mr Baker compiled a list of 27 Tory colleagues he claimed were considering voting for changes to Ms May’s Brexit plans, accusing them of seeking to overturn the referendum.
At the time, Mr Baker said: “This is a time to unite behind a democratic result, not plot to repudiate it. Any vote to amend this simple bill is a vote against implementation of the referendum result.”
Mr Baker is also under pressure to reveal his links to a group that donated £435,000 to the DUP to campaign for Brexit during last year’s referendum.
The MP was handed £6,500 by the obscure Constitutional Research Council, the body which used a legal loophole to channel the money to the DUP.
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