The UK's new Prime Minister will not be allowed to bring a new Brexit deal to the table, European officials said today.
A European Commission spokesman said the Brexit deal that is on the table "has been approved by all member states", adding that "a new prime minister will not change the parameters."
When asked about a pledge from Boris Johnson, the favourite to succeed Theresa May, to withhold billions in liabilities owed to the European Union's budget, the spokesman said: "Everybody knows what is on the table.
"What is on the table has been approved by all member states and the election of a new prime minister will not change the parameters."
It came as several more Conservative candidates embarked on their efforts to become Tory leader by making speeches today.
Andrea Leadsom and Mark Harper have already delivered speeches, while Rory Stewart is due to make his speech later today.
Ms Leadsom said: "With a government whose policy is to leave at the end of October in all circumstances, my view is that putting forward sensible measures that Parliament will agree to, and that I believe the EU will also find very sensible, that have already been agreed in the Withdrawal Agreement, I think that we will have success."
But she made clear the October 31 deadline was a "hard, red line."
Mr Harper said he would go back to Brussels to re-negotiate the Northern Ireland backstop.
While he said he would not take no-deal off the table, he warned the parliamentary arithmetic meant no new leader could promise to take the UK out by the latest EU deadline of October 31.
He said: "One thing I'm not promising, as much as I'd like, is that we will leave deal or no-deal come October 31."
Earlier, Nicola Sturgeon said Brexit and the "horror show" of the leadership contest are signs that Scotland needs to chart a different path, probably outside the UK.
Ms Strugeon, who held talks with EU Brexit negotiator Michel Barnier, and was due to meet later with European Commission president Jean-Claude Juncker, said: "Increasingly, Scotland and the UK are on different political paths.
"We have to confront whether the better response to that is to have the ability to be independent and shape our own future."
"The people of Scotland have to have a choice before it's too late to stop the damage of Brexit being done."
