Two Tory leadership candidates have clashed over whether they would shut down Parliament early to force through a no-deal Brexit.
Esther McVey said the measure was part of a “toolkit” that could be used to ensure Brexit is delivered on time.
But Michael Gove said such a move would be “wrong” and contradict “the best traditions of British democracy”.
Eleven Conservative MPs are vying to replace Theresa May as party leader and, ultimately, prime minister.
The candidates have been laying out their policies on Brexit and other issues before nominations close at 17:00 BST on Monday. They need eight MPs to back them or they are eliminated from the contest.
Jeremy Hunt, another leadership contender, said the EU would be “willing to negotiate” on the Brexit deal if the UK takes the “right approach”.
Speaking on Sky News on Sunday, the foreign secretary said he had spoken with German Chancellor Angela Merkel and suggested she was open to looking at new solutions for the Irish border issue in talks.
“She said that […] with a new British prime minister, we would want to look at any solutions you have,” he added.
Asked whether she would consider using ending the current session of Parliament – a process known as prorogation – to force through a no-deal Brexit, Ms McVey said it would not be her “priority” and she would “not be looking to do that” as prime minister.
But the former work and pensions secretary told the BBC’s Andrew Marr Show: “I’ve said I’d use every tool at my disposal, so that would include that.”
She also said MPs who wanted to “frustrate” the Brexit process had “ripped up the rule book” and were guilty of “tearing up 400 years of history”.
Environment Secretary Michael Gove said MPs who had voted to start Brexit talks by triggering Article 50 should respect the result of the vote to leave the EU, but halting Parliament would “not be true to the best traditions of British democracy”.
Earlier, he said that he would replace VAT with a “lower, simpler, sales tax” in an interview in the Sunday Telegraph.
Could prorogation be used to push through no deal?
If a new prime minister is concerned about MPs blocking the UK’s exit from the EU, they could advise the Queen to prorogue Parliament.
This would send MPs away so that they cannot do anything in the Commons to hold up Brexit.
However, it would be an unprecedented move in modern times to use this power for political reasons, rather than to end a session in preparation for a new Queen’s Speech.
Fellow Tory leadership candidate Dominic Raab has also suggested he would be prepared to shut down Parliament to ensure the UK leaves the EU on 31 October.
The suggestion has led to criticism from a number of MPs, with Commons Speaker John Bercow saying prorogation to enforce a no-deal exit is “simply not going to happen”.
‘Scylla and Charybdis’
Meanwhile, Boris Johnson – in his first major interview of the campaign – compared the Labour and Brexit Party leaders to sea monsters from Greek mythology.
“I truly believe only I can steer the country between the Scylla and Charybdis of Corbyn and Farage and on to calmer water,” he told the Sunday Times.
Mr Johnson said as prime minister, he would refuse to pay the EU a £39bn settlement until there was “greater clarity” about a future relationship.
He also said he would scrap the Irish backstop and would only settle the border issue when Brussels was ready to agree to a deal.
Welsh Secretary Alun Cairns, Transport Secretary Chris Grayling and Housing Secretary James Brokenshire have all declared their support for Mr Johnson’s leadership bid.
The former foreign secretary has also won the backing of Brexit Minister James Cleverly, who became the first Tory MP to pull out of the leadership race on Tuesday.
Who will replace Theresa May?
The winner of the contest to lead the Conservative Party will become the next prime minister.
Home Secretary Sajid Javid, another MP hoping to become Tory leader, told Sky News his offer to pay Ireland for new technology to ensure a frictionless Irish border would “change the dynamic” in Brexit talks.
Mr Javid also said he would pay for a “multi-billion pound” spending increase in education by slowing down government debt repayment.
He said that could free between £15bn and £25bn a year, some of which would go to the education system.
Mr Javid has won the backing of Scottish Conservative leader Ruth Davidson, who wrote in the Scottish Mail on Sunday that he had a vision to unite a “divided Britain”.
In his Sky interview, Jeremy Hunt also repeated his support for lowering the standard legal time limit for abortion from the current 24 to 12 weeks, but added that it would not be government policy to change the law if he became PM.
After nominations close on Monday, MPs will then vote for their preferred candidates in a series of secret ballots held on 13, 18, 19 and 20 June.
The final two will be put to a vote of members of the wider Conservative Party from 22 June, with the winner expected to be announced about four weeks later.