The Tory war over Europe has exploded dramatically once more after a Cabinet minister attacked a Government study of “Brexit” as a “dodgy dossier”.
The official document, which is due to be published on Wednesday, warns that "Britain would be weaker, less safe and worse off outside the EU”.
It claims that all the alternatives to EU membership - such as those currently used by Norway, Switzerland and Canada - would harm the UK’s trade, jobs and security.
But in his bitterest attack yet on David Cameron’s tactics, Work and Pensions Secretary Iain Duncan Smith lambasted the claims by the 'Remain' in the UK campaign.
With the EU referendum due to take place on June 23, he compared the document to Tony Blair’s infamous “dodgy dossier” claiming Saddam Hussein had weapons of mass destruction.
Foreign Secretary Philip Hammond insisted today that the assessment was a "hard-headed analysis” of the facts of what life would look like outside the EU.
The study of the various options, which the Government is required to produce under its own Referendum Act, finds that in every case "huge numbers of British companies with supply chains in Europe would suffer”.
A Norway-style deal with Brussels would fail to stop immigration, a Swiss deal would mean no control over EU rules and a Canada-style trade plan would take years to complete and inflict damage on the City of London, the document concludes.
It also warns finds the option that would offer the cleanest break with the European Union - reverting to World Trade Organisation rules - would lead to huge new tariffs on UK exports to the EU, leading to rises in food prices for shoppers.
Mr Duncan Smith, who was backed by former Chancellor Norman Lamont and former welfare minister Esther McVey today, was vitriolic about the latest Government attempt to influence voters.
"This dodgy dossier won’t fool anyone, and is proof that Remain are in denial about the risks of remaining in a crisis-ridden EU,” he said.
"The truth is, we won’t copy any other country’s deal. We will have a settlement on our own terms - and one that will return control of our borders, and money to Britain. That’s the safer choice."
Mr Hammond said: "Hard-headed analysis shows that every alternative to remaining in a reformed EU would leave Britain weaker, less safe and worse off.
"Working people would pay the price with fewer jobs and rising prices. Our special status gives us the best of both worlds: in the parts of Europe that work for us, but outside those that do not.”
It is “for them to spell out” a “credible picture” of life outside the EU, Mr Hammond told Radio 4’s Today programme this morning. “That is completely missing. They are offering us nothing,” he said, adding the Government was “analysing the evidence” of whether EU arrangements with non-members countries “worked for Britain”.
“Our conclusion is they wouldn’t,” he said.
Questioned why David Cameron had said before his “deal” the UK could “survive outside Europe”, Mr Hammond said: “No-one is saying we would be in some terrible situation, but the Leave campaign has to explain how they would deal with these trade-offs.
“It is not credible to say you would have continued access to the single market without having to accept free movement of labour, without having to accept EU regulations, and without having to contribute to the EU budget.”
But 'Out' campaigners say Britain could carve its own unique trade deal with Brussels and point to polling data suggesting that neither Switzerland nor Norway show any inclination towards joining the EU.