A number of backbench Tories have written to Jeremy Corbyn, claiming his party is "betraying the national interest" by damaging the Brexit process.
A letter written by Suella Fernandes and signed by 18 other MPs including Owen Patterson, Crispin Blunt and Charlie Elphicke, said Labour's position on a 'no deal' could do "material harm to Britain's negotiating position" when it comes to Brexit.
Fernandes stressed that no deal "is not one we seek" but stressed the need to take it seriously in order to refuse bad deal scenarios, which she said included the continuation of free movement of labour, and remaining in the single market as well as continuing to pay into the EU's budget.
"If the negotiations have taught us one thing so far, it's that the EU have played hardball with issues that affect people's lives and we must use all our leverage to protect the national interest," the letter said.
"There are those in the EU for whom the sole priority in these negotiations is that they punish Britain: your policy would give them strength."
She also called on Corbyn to "discipline" the 18 Labour MEPs who voted to block Brexit negotiations from progressing to the next stage, which will allow David Davis and his counterpart Michel Barnier to discuss trade and transition. The vote was only advisory, with the real decision being taken by the EU27 leaders this Friday.
Davis has already written to Corbyn saying he was "disappointed" by the rebellion last week and asking him to reprimand those involved.
Fernandes' letter does not mention the Conservative MEPs Julie Girling and Richard Ashworth who were suspended from the party after they also voted against moving to the second phase of discussions.