The prime minister has warned Conservative MPs that they could be 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".
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".
Mrs May said she has not seen any workable alternative to the White Paper - so voting against her legislation could lead to a "disorderly and damaging Brexit".
The prime minister said the legacy of Brexit "cannot be a hard border between Northern Ireland and Ireland".
She added that Brexit must not destroy the "integrated supply chains and just-in-time processes on which jobs and livelihoods depend".
But Mrs May did offer some reassurance to those who worry she will make further concessions to Brussels.
"Our Brexit deal is not some long wish-list from which negotiators get to pick and choose," she wrote.
"It is a complete plan with a set of outcomes that are non-negotiable."
She added her Brexit plan would "end" both the free movement of people and the jurisdiction of the European Court of Justice in the UK.
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.
Key dates at-a-glance
18 October 2018: The key EU summit. Both sides hope to agree outline of future relations to allow time for UK parliament and EU members to ratify deal by Brexit day
13 December 2018: EU summit. If deal not done by October, this is the fall back option if the two sides still want to reach agreement
Commons and Lords vote on withdrawal treaty - MPs could reject the deal but it's not clear what would happen if that is the case
The UK Parliament also needs to pass an implementation bill before Brexit day
29 March 2019: As things stand, deal or no deal, Brexit is due to happen at 11pm UK time
31 December 2020: If all goes to plan a transition period will then last until midnight on this date
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.