Former Chancellor Philip Hammond has hit out at suggestions Tory MPs who vote against a no-deal Brexit could be sacked.
Mr Hammond responded to reports which suggest Conservative rebels could be forced out should they defy the Government in a touted Commons show down next week.
The Sun reported that those who do defy the whip will be banned from sitting for the party in their seats at the next general election.
Writing on Twitter, Mr Hammond said: “If true, this would be staggeringly hypocritical: 8 members of the current cabinet have defied the party whip this year.
“I want to honour our 2017 manifesto which promised a “smooth and orderly” exit and a “deep and special partnership” with the EU.
“Not an undemocratic No Deal.”
Mr Hammond has been a prominent opponent to Boris Johnson’s stance on no-deal, calling a hard Brexit a “betrayal of the referendum”, despite the PM’s insistence it should not be ruled out despite also stating he wants a deal.
A Government spokesperson said: “All options for party management are under consideration, but first and foremost the PM hopes MPs will deliver on the referendum result and back him on Parliament.”
The former Chancellor’s comments come as Boris Johnson faced a continued backlash on his plans to prorogue Parliament.
The Queen agreed to the suspension from no earlier than September 9 and no later than September 12 to October 14.
Earlier today, Mr Hammond’s successor as chancellor Sajid Javid backed the PM’s move.
Despite insisting during the Tory leadership campaign he thought proroguing Parliament was a bad idea, Mr Javid has now said the Government needs time to focus on its agenda in the run-up to outlining plans in October’s Queen’s Speech.
He told BBC Radio 4’s Today programme: “It is quite usual this time of year, Parliament goes into what’s called a conference recess and it doesn’t usually sit for some time in September and early October.
“It’s right because we are focusing on the people’s priorities.”
Pressed on his comments during the Tory leadership battle that prorogation could be seen as “trashing” democracy, the Chancellor said: “I wasn’t being asked about a Queen’s Speech, a Government setting an agenda, that was a question around suspending Parliament for the sake of it for months on end in order to avoid debate.”
While health secretary Matt Hancock has similarly addressed comments he made in his own leadership bid.
Mr Hancock said on Saturday that his comments during the Tory leadership campaign were in relation to a plan for a much longer suspension, saying there is a “substantive” difference between that idea and what is actually happening.
Asked to explain his apparent change of stance at the Big Tent Ideas Festival in east London on Saturday, Mr Hancock said: “During the leadership debate there was a discussion of an idea that some people brought forward that from the new prime minister taking over, up to and through the first of November, Parliament will be prorogued in order to drive through what would effectively be a no-deal Brexit.
“And I didn’t support that idea. And I spoke about it in quite passionate terms.
“There’s some people who are saying that Parliament will be suspended. Well it doesn’t feel like it to me.”
Meanwhile, Tory former PM Sir John Major said he wanted to join a legal challenge to Mr Johnson’s decision to extend the suspension of Parliament over the annual party conference season.
Sir John suggested his experience in Downing Street could assist the High Court in deciding whether Mr Johnson’s actions in proroguing Parliament are lawful.
Mr Johnson defended his decision and warned that efforts to frustrate Brexit on October 31 would be seized on by Brussels to avoid offering a good deal.
Businesswoman Gina Miller – who previously took the Government to court over the triggering of Article 50 to start the Brexit process – said her case would be heard on September 5.
Shadow attorney general Shami Chakrabarti said she has been granted permission to intervene in the judicial review, as she accused the Government of operating from a “far-right playbook”.
Baroness Chakrabarti said: “I am grateful to the High Court for granting me permission to intervene in these important proceedings on behalf of the official opposition.
“Parliamentary sovereignty remains the foremost and overarching principle of our constitution.
“Whatever far-right playbook Number 10 may be copying from, the abusive shutdown of our legislature won’t wash under United Kingdom constitutional law.”
In a separate legal case in Scotland, judge Lord Doherty rejected a call for an interim interdict to block the suspension of Parliament, but said a full hearing would take place on Tuesday.