Owen Paterson among Tory MPs to sign letter spelling out demands to stop Euro budget payments

The letter, circulated among members of the Conservative European Research Group of Brexit-backing MPs by Change Britain, also states that remaining in the single market during a transition would be an “historic mistake”.

It will be viewed as an attack on attempts to soften Brexit and on Labour’s position of demanding single market membership during a transition period after the UK’s official exit from the European Union in March 2019.

But demands to stop paying into the EU budget and having the ability to sign free trade deals during that period may make it more difficult for ministers to negotiate a deal with minimum disruption to avoid a “cliff-edge” Brexit.

Ministers have made clear that Britain will quit the single market and customs union in March 2019, but have admitted the UK would not be able to implement free trade agreements during a proposed transitional customs deal.

The letter, which was intended for publication in a Sunday newspaper but leaked, warns against any attempt to keep Britain in the EU “by stealth”. Itreads: “Continued membership of the single market, even as part of a transitional arrangement, would quite simply mean EU membership by another name – and we cannot allow our country to be kept in the EU by stealth.

“The Government must respect the will of the British people, and that means leaving the single market at the same time as we leave the EU.”

Confirming he was one of the signatories, Mr Paterson said: “There is no such thing as a hard Brexit. We either have Brexit or we don’t.”

"Here’s why:

“Continued membership of the ‘single market’ (the ‘Norway option’) - the stated goal of the Labour Party - would be an historic mistake.

“The truth is that the ‘single market’ is a political project, and requires its members to constantly introduce new EU laws.

“Therefore, the longer one remains a member the harder it is to leave. Contrary to claims that it is a ‘sensible’ stepping stone to independence, it is in fact a conveyor belt to ever more European integration.

“What’s more, for as long as we remain in the single market, we will have to make payments into the EU budget, and will be unable to take advantage of the freedoms available as a result of leaving the EU - such as the ability to deport foreign criminals.”

The latter also urges the Government to ensure a transitional deal sets out “a clearly defined timetable for this country’s departure from the single market and customs union” and has safeguards allowing the UK to withdraw unilaterally. The letter adds: “We need to make sure the UK is not forced on to a conveyor belt of EU regulation.

“The European Communities Act 1972 must be repealed, in full, on exit day. Likewise, on exit day, we must ensure we are exempted from Article 3 TFEU.”

“There can be no Henry VIII laws which automatically add EU/EEA laws onto our statute books, and we must be free to negotiate and sign trade deals during the transition period. Finally, the UK must have the power to take back control of key parts of its immigration system. In short, when we leave in 2019 - we need to make sure we are well and truly out.

“With these clauses in place the will of the British people will have been respected and the country set on a course to make a great success of Brexit.”