Brexiteer Jacob Rees-Mogg has urged Theresa May to "chuck Chequers" and "believe in Britain" in a letter to grassroots Conservatives.
The backbench Tory and 60 colleagues have signed the letter, which describes the Prime Minister's Brexit Chequers compromise as the "wrong deal for Britain".
It states the UK "does not need to do a deal with the EU", but the bloc "needs to do a deal with us at all costs".
In the letter, leaked to the Telegraph, Mr Rees-Mogg says: "The Government would be wrong to be fearful of Britain enjoying an independent future. Theresa May's Chequers proposals would shackle us to the EU forever.
"We would be out of Europe yet still run by Europe. This is why the Prime Minister should 'chuck Chequers' and instead seek a Canada-style free trade agreement with the EU to make the most of the global opportunities that lie ahead.
"It is time the Government realised that the EU stands to lose much from no deal being agreed and stopped being cowed by the EU's threats.
"It is time to face down vested interests in the establishment and put democracy first. Yet most of all, it is time 'to chuck Chequers', respect the referendum, be out of Europe, take back control and believe in Britain."
The briefing note states the Chequers deal would "prevent taking back control of our borders", and warns proposals for "reciprocal mobility arrangements" are "dangerously close to free movement".
The intervention comes as the Government prepares to publish papers outlining its planning for a possible no-deal Brexit.
Brexit Secretary Dominic Raab is due to give a speech on Thursday to coincide with the release of the first of a raft of papers on more than 80 subjects.
It follows his assurances that EU citizens living in the UK will not be "turfed out" if no deal is agreed with Brussels, as he vowed to "move swiftly" to safeguard their future.
Mr Raab said he is confident of reaching an agreement, but sought to reassure those living in Britain that ministers would act quickly to secure their position if the UK crashes out of the EU.