The prime minister has warned Conservative party members that they are putting Brexit at risk.
Some long-standing Leave campaigners are unhappy with her Brexit White Paper which proposes a common rulebook with the EU for traded goods.
Writing in the Mail on Sunday, Theresa May urged the country to “keep their eye on the prize”.
Her message comes ahead of crucial Commons votes on trade and customs policy next week.
Some members of her party’s European Research Group (ERG) want to amend that legislation to scupper Mrs May’s plans.
The White Paper, which sparked the resignations of ministers Boris Johnson and David Davis, is aimed at ensuring trade co-operation, with no hard border for Northern Ireland, and global trade deals for the UK.
Tory Brexiteer Jacob Rees-Mogg called it a “bad deal for Britain” and US President Donald Trump told the Sun newspaper the proposals would “probably kill” a trade deal with his country.
Hours later however, he said a US-UK trade deal would “absolutely be possible”.
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Mrs May argues in her article that she has not seen any workable alternative to the White Paper so voting against her legislation could lead to a “disorderly and damaging Brexit”.
But she also offers some reassurance to those who worry that she will make further compromises in order to reach a deal with Brussels.
“Our Brexit deal is not some long wish-list from which negotiators get to pick and choose,” she writes.
“It is a complete plan with a set of outcomes that are non-negotiable.”
Long-standing Leave campaigners are not the only group likely to revolt, however.
There are also fears that some former Remainers in her party will vote with Labour to compel her to negotiate a fully-fledged customs union with the EU.
“This would be the ultimate betrayal of the Brexit vote,” she says.
On Thursday, the EU’s chief negotiator Michel Barnier said he would analyse the details with the European Parliament and member states and was “looking forward” to negotiations with the UK next week.
The UK is hoping the EU will back the White Paper proposals so an exit deal can be struck by the autumn, ahead of the UK’s official departure from the EU in March.
Theresa May will be interviewed live on The Andrew Marr Show on Sunday. The programme will be broadcast at 09:00 BST on BBC One.
PM Theresa May warns party not to put Brexit at risk}