GETTY The Government faced pressure to speed up Brexit and cut ties with Brussels

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The leading Brexit group, Leave Means Leave, has called on ministers to spell out the harm Britain can do to the economy of the remainder of the EU if leading Brussels figures continue to try to “punish” the UK in what is being dubbed “Empire Strikes Back”. The intervention by the group backed by many senior Tory MPs and former ministers, was made as Margaret Thatcher’s former economic advisor Patrick Minford condemned pro-EU “fifth columnists” in the Treasury for leaking a document claiming hard Brexit would cost Britain £66 billion. The document was drawn up in April on the orders of former Chancellor George Osborne as part of the discredited Project Fear campaign.

The barrage from Remain supporters and the EU has prompted fears that ministers are being too soft over the opponents lined up against Britain’s bid for freedom and prosperity away from Brussels rule. In particular there is outrage over the tactics of former Labour leader Ed Miliband, Lib Dem ex-Deputy Prime Minister Nick Clegg and sacked Tory business minister Anna Soubry - known as the “remoaners” - to use parliamentary procedure to undermine the Brexit negotiations. The three are major backers of a Labour sponsored debate today aimed at forcing ministers to seek MPs approval for their negotiation strategy and putting in a condition that the UK stays in the single market which would halt Brexit. Meanwhile, one of Britain’s leading manufacturing companies JCB has resigned from the Confederation of British Industry (CBI) over its attempts to keep Britain in the EU.

GETTY Chancellor Angela Merkel and President Francois Hollande want to 'punish' the UK for Brexit vote

The company’s owner Lord Bamford was furious after leaders of the CBI claimed a hard Brexit option could see tariffs imposed on 90 per cent of British exports ignoring evidence that it will free Britain to trade around the world. Leave Means Leave warned that Britain needs to take a much stronger line against leading EU figures who are trying to bully and intimidate Britain into reversing the result. The group has said that ministers need to spell out that Britain can inflict far more damage in a trade war with the fragile EU bloc than it can on the UK. It follows calls by German Chancellor Angela Merkel and French President Francois Hollande to “punish” Britain for voting to Leave.

The aggressive line has also been picked by senior EU figures including European Investment Bank boss Werner Hoyer threatening to “end” cheap loans and starve the UK in submission, while Frankfurt is attempting to poach banks from the City of London. Leave Means Leave has demanded that Britain sets a clear two year deadline to get out of the EU when Article 50 is triggered next year. Last night one senior member of the group, MEP David Campbell Bannerman, who sits on the European Parliament’s trade committee, said: “These empty threats are a totally misguided attempt by the EU empire to strike back. “Our Government is in the stronger position and needs to stand up against the EU and spell out the dangers such an approach could have on the negotiations. “If the EU do not secure a trade deal with the UK, the shockwaves could bring down the Eurozone.”

GETTY Leave Means Leave chairman Richard Tice warned pro-EU politicians aren't democratic

In a direct attack on Remainer MPs attempting to derail the Brexit negotiations, Leave Means Leave chairman Richard Tice warned that pro-EU politicians in the UK “do not share our belief in democracy”.

Our Government is in the stronger position and needs to stand up against the EU MEP David Campbell Bannerman

He said: “Foreign leaders and senior figures in the EU have pursued an aggressive, threatening rhetoric ever since the British voters rejected their failing club. “They will stop at nothing to save their crumbling European project.” He added: “The leak from the Treasury is nothing more than a continuation of the Project Fear rejected by the public during the referendum campaign and condemned at the time.” He pointed out that it was commissioned by George Osborne as part of the referendum Project Fear campaign.

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Mr Tice went on: “Project Fear claimed Brexit would put a bomb under our economy and trigger a recession, and this has not happened. “The leaked document is nothing but a dated piece of propaganda from a discredited former Chancellor.” Instead of the economy collapsing as predicted by the Treasury the FTSE is at one of its highest levels historically and former Bank of England Governor Sir Mervyn King has welcomed the devalued pound as being at its natural level and boosting exports. Senior Tory backbencher Jacob Rees Mogg has also attacked Treasury officials for releasing the out of date figures. He said: ”It’s thoroughly irresponsible for the Treasury to be producing documents that will encourage the EU to offer us a bad deal.”

GETTY Brexit secretary David Davis warned that a 'punishment' agenda by the EU will fail