Jacob Rees-Mogg sparked a clash with the prime minister by suggesting that Britain keep its borders open after Brexit

Theresa May confronted Jacob Rees-Mogg at a meeting with Tory MPs designed to break the deadlock over Britain’s future customs arrangements with the EU, The Times has learnt.

The pair clashed yesterday over the impact of rival plans on the Irish border, in what witnesses described as the prime minister “sending a tough signal” to hardline Brexiteers that she was not prepared to jeopardise the Union.

It came after Mrs May went over the heads of her squabbling cabinet with a personal appeal to scores of backbench Tory MPs to help to settle Britain’s position. She issued an open invitation to all 315 Conservative MPs to attend Downing Street briefings on the rival options that have split her top team.

It followed an appeal to