Boris Johnson is set to tell Angela Merkel and Emmanuel Macron that parliament cannot stop a no-deal Brexit in an attempt to get a new deal with Europe.
Johnson will make clear to the French president and German chancellor that Britain will leave the European Union on October 31 with or without a deal.
The PM, who is heading to Berlin and Paris this week, is expected to say that parliament will not and cannot cancel the outcome of the EU referendum.
He will insist there must be a new deal to replace Theresa May’s thrice-defeated Withdrawal Agreement if Britain is to leave with a settlement on October 31.
However, Number 10 said it expects there will be “very little discussion” of Brexit during the visits, predicting that each side would state its position and then move on to other topics.
Instead, it is thought the discussions will revolve around next weekend’s G7 agenda – with topics including foreign policy, security, trade and the environment likely to dominate.
Johnson will meet world leaders at the summit in Biarritz, France, where he will seek to spread the message of the UK’s “renewed global reach”.
He is also expected to discuss how states can work together to address challenges facing the world’s biggest economies, such as fears about the financial system, security issues and climate change.
Meanwhile, the Mail on Sunday reported that Johnson has accused former chancellor Philip Hammond of “gravely damaging” the national interest with his bids to frustrate Brexit.
In a letter seen by the paper, the PM said it was “plain as a pikestaff” that the EU “will simply not compromise as long as they believe there is the faintest possibility that Parliament can block Brexit on 31 October”.
The Sunday Telegraph reported a Downing Street source accusing Tory Remainers of “appalling dishonesty” for attempting to use the Brexit delay to “cancel the referendum”.
The paper also said that Brexit Secretary Stephen Barclay has signed the “commencement order” that will trigger the end of the supremacy of EU law in the UK on October 31.