Amber Rudd has sensationally quit the British cabinet and the Conservative Party in protest at Boris Johnson's handling of Brexit.
The MP has quit her post as work and pensions secretary and said she was relinquishing the Tory whip after the British prime minister sacked 21 rebels this week.
Mr Johnson removed the whip from two former chancellors and Winston Churchill's grandson after they voted to give opposition MPs control of the order paper and start the process of blocking a no-deal Brexit.
Ms Rudd said: “I cannot stand by as good, loyal moderate Conservatives are expelled.
“I have spoken to the PM and my Association Chairman to explain. I remain committed to the One Nation values that drew me into politics.”
In comments likely to reverberate across Westminster as it gears up for another tumultuous week, Ms Rudd said she thought a no-deal Brexit was now the British government’s main aim.
The former home secretary was dogged by questions throughout the Tory leadership contest about whether she could serve in Mr Johnson's cabinet if he won the race, given his strategy would involve keeping no-deal on the table during further negotiations with Brussels.
She accepted the offer of continuing in her job as work and pensions secretary when Mr Johnson formed his cabinet in July.
But in her letter of resignation, the now independent MP said that while she had accepted the need to keep no-deal as an option, she said she “no longer believed leaving with a deal is the Government’s main objective”.
Issuing forthright criticism of Mr Johnson, she called his decision to sack Tory rebels — such as ex-chancellor Philip Hammond, Churchill’s grandson Sir Nicholas Soames and Ken Clarke, the longest serving MP in the commons — an “assault on decency and democracy”.
Ms Rudd, who was also minister for disabled people, added: “This short-sighted culling of my colleagues has stripped the party of broad-minded and dedicated Conservative MPs. I cannot support this act of political vandalism.
“Therefore, it is with regret that I am also surrendering the Conservative whip.”
Ms Rudd has represented her constituency since 2010 and has one of the smallest majorities in the country, with only 346 votes separating her from her Labour rival in 2017.
Ian Lavery, Labour Party chairman, said Ms Rudd’s sudden resignation was a sign that “no-one trusts” the PM.
“The Prime Minister has run out of authority in record time and his Brexit plan has been exposed as a sham,” he said.
"No-one trusts Boris Johnson. Not his Cabinet, not his MPs, not even his own brother.
“After nine years of austerity, we need a Labour government that will invest in our communities and public services.”
Earlier it emerged that British MPs were preparing legal action in case Boris Johnson tries to defy legislation compelling him to seek a further delay to Brexit, Labour Party leader Jeremy Corbyn said on Saturday.
An opposition bill which would force the British prime minister to ask the European Union for an extension to Britain's departure to avoid an October 31st exit without a transition deal was approved by the House of Lords on Friday.
Britain's Queen Elizabeth is expected to sign it into law on Monday.
The BBC said earlier that MPs, including moderate Conservatives expelled this week from their party for backing the bill, have lined up a legal team and are willing to go to court to enforce the legislation if necessary. The government had no immediate comment.
Mr Johnson, a leader of the campaign to leave the EU during the 2016 Brexit referendum, took office in July after Conservative party predecessor Theresa May quit following three failed attempts to get a deal with Brussels through parliament.
The new prime minister vows to take Britain out of the EU on October 31st, with or without a deal. Mr Johnson has said he has no intention of seeking an extension and would rather "die in a ditch" than delay Brexit. One of the main stumbling blocks is the provision in the withdrawal agreement, the backstop, that guarantees an open border between the Republic of Ireland and Northern Ireland if no trade deal is reached in the two-year transition period after Brexit.
Saturday’s Daily Telegraph reported that the prime minister is prepared to defy parliament’s instruction to request an extension to the Brexit process if he fails to agree a new deal. The newspaper quoted Johnson as saying he was only bound “in theory” by the new legislation.
But a former director of British public prosecutions (DPP) told Sky News that Mr Johnson could face prison if he refuses to delay Brexit in the face of court action.
It quoted Ken MacDonald, DPP in 2003-2008, as saying that legal action would result in a court ordering that the law should be followed: “A refusal in the face of that would amount to contempt of court, which could find that person in prison.”
Mr Corbyn said Labour was not as a party taking legal action but was aware of manoeuvres on the matter.
“The courts making a decision to try to make a prime minister abide by the law, made by a parliament, of which he is a member. These are strange times for democracy,” Mr Corbyn told BBC television.
An opinion poll on voting intentions, carried out by Survation for the Daily Mail, put the Conservatives on 29 per cent, down 2 per cent from the previous poll, with Labour unchanged on 24 per cent. The Liberal Democrats were on 18 per cent and the Brexit Party 17 per cent.
David Lidington, who was deputy prime minister under Mrs May, said that obeying the rule of law was a fundamental principle of the ministerial code. "Defying any particular law sets a really really dangerous precedent," he told BBC radio. Mr Lidington resigned just before Mr Johnson took office.
Mr Johnson says the only solution to the Brexit deadlock is a new election, which he wants to take place on October 15th and could give him a new mandate to quit the EU on schedule.
Two-thirds of MPs need to back an early election, but opposition parties, including Labour, said they would either vote against or abstain on this until the law to force Mr Johnson to seek a Brexit delay is implemented.
“We need a clear statement from the prime minister that he is going to abide by that act of parliament,” Mr Corbyn said.
Mr Johnson failed to win enough support in a vote on Wednesday for an election. Another vote is scheduled for Monday. - Reuters