They have signed a letter calling on the Prime Minister to lay down red lines when she meets European Commission president Jean-Claude Juncker and his chief negotiator Michel Barnier in Brussels.
The move comes amid continuing brinkmanship ahead of a summit later this month where EU leaders will decide whether to give the go-ahead to the next round of Brexit negotiations, including talks on a free-trade deal.
The hard-hitting letter, organised by Leave Means Leave and signed by business leaders and politicians across the political divide, accuses EU negotiators of acting in “a manner sadly unbecoming of an international body”.
It also accuses the EU of demanding “vast sums of money from the UK but declining to set out what the UK will get in return”.
Arguing that the conciliatory tone struck by the PM has not been reciprocated, it sets out a series of demands that should be met by Brussels before Britain agrees to make a “reasonable, realistic and not extortionate goodwill payment”.
These include reaching a free trade deal in principle with no tariffs by next March, ending the jurisdiction of EU courts when the UK leaves the bloc and allowing Britain to negotiate agreements with other countries during the transition period.
The letter also calls for an end to freedom of movement at the end of March 2019 and an agreement on the border between Northern Ireland and the Republic.
It argues that if the EU refuses to agree to these terms by the end of the December summit then the UK should suspend further talks and say it will revert to World Trade Organisation rules on Brexit.
Signatories to the letter include ex-Tory chancellor Lord Lawson, former Conservative Cabinet ministers Owen Paterson and John Redwood, Tory MP Jacob Rees-Mogg, Labour MP Graham Stringer, JD Wetherspoon pub chief Tim Martin and entrepreneur and Labour Leave founder John Mills.
Mr Paterson said: “No money should be handed over until we have a clear commitment to reciprocal free trade with no tariff.
“If they don’t agree to that then tough, we will go to WTO rules. It’s not no deal, it’s a global deal.”
The pressure has been ramped up with backbench Brexiteers threatening to vote down any EU deal unless the Government agrees to pay the divorce bill in a lump sum, rather than instalments.
Angered by reports that Mrs May and her Cabinet have agreed to double the £20billion Britain plans to give Brussels, Tory MPs and their Eurosceptic Labour colleagues are demanding a single payment in return for a “gold-plated” deal.
In exchanges seen by the Sunday Express, a number of MPs express concerns they will not be able to sell a £40billion bill “on the doorstep”.
One Tory MP said: “The EU seems to want to keep us in an abusive relationship by putting up the divorce bill so we can’t afford to leave.
“Backbenchers have been expressing their unhappiness to the whips. There’s a sense that £40billion isn’t going to wash with the public unless it unlocks a brilliant future trading relationship with Europe on similar terms to the ones we have now.”
December 3rd, 2017: Express