European leaders should not listen to the “very wrong messages emerging from parliamentarians” who want to stop Brexit, a senior British official says.
Speaking at the G7 summit in Biarritz, the official said the PM had been clear to European leaders that the idea Brexit will be stopped was “incorrect”.
Cross-party talks on how to avoid no deal are due to take place on Tuesday.
But Boris Johnson has repeatedly insisted that the UK will leave the EU on 31 October, with or without a deal.
The SNP, Liberal Democrats, Change UK, Plaid Cymru and the Green Party have all accepted the invitation to meet Labour leader Jeremy Corbyn to discuss proposals for an alternative government to be formed when Parliament returns in September.
If he wins a no-confidence vote, Mr Corbyn plans to form an emergency government, with himself as a caretaker prime minister, and then delay Brexit to avoid a no-deal scenario.
However, Jo Swinson, the leader of the pro-EU Liberal Democrats, said his plan risks jeopardising a vote of no confidence in the government.
At the G7 summit, the senior British official said: “We are leaving on October 31 with a deal or without.
“The prime minister would prefer it to be a deal but we will be leaving on October 31 and he is very clear about that.
“He thinks European leaders should not be listening to the very wrong messages emerging from some parliamentarians who think that they will stop Brexit.”
The official said Mr Johnson has been “repeatedly clear that parliamentarians and politicians don’t get to choose which public votes they respect”.
If a new Brexit deal was negotiated, the public would “expect Parliament to find a way” to pass the necessary laws to allow the UK to leave at the end of October.
The G7 summit – a get-together of most of the leaders of the world’s largest economies – comes with just over two months until the UK is scheduled to leave the EU.