Labour Party whips will defy leader Jeremy Corbyn over his stance on Brexit
Jeff Smith and Thangam Debbonaire, both Labour Party whips, said they would rebel over an instruction to Labour MPs from Mr Corbyn's office to back the Government bill to trigger Brexit.
Their announcement followed the resignation of Tulip Siddiq from the shadow ministerial team as she announced she would join hard line Lib Dem and SNP Remoaners in ignoring the democratic will of the British people and vote against starting the Leave process.
Shadow transport minister Daniel Zeichner has also said he will defy Mr Corbyn.
The chaos has underlined the deep splits within Labour over Brexit and inability of Mr Corbyn to control his own MPs.
The leadership is also sending out mixed messages with shadow Brexit Secretary Sir Keir Starmer stating that he plans to put down 50 amendments which could derail or delay the Article 50 bill.
Bristol West MP Ms Debbonaire said she was prepared to lose her job as a whip in order to represent her Remain-supporting constituency.
The chaos has underlined the deep splits within Labour over Brexit
Ms Debbonaire said: "I have always said that I would be minded to vote against Article 50 if it meant leaving the single market, or something close to it. And Theresa May has indicated that that is what she wants to do, so I'm minded to vote against.
"I love being in the whips' office. I like being part of a team that's trying to bring the party together. But the people who matter most are the people of Bristol West."
Mr Zeichner – whose Cambridge constituency voted for Remain in the referendum – saying he would defy his party leader because it was a "very straightforward decision" for him to take.
Mr Corbyn has asked for the Labour party to back the Government's Brexit plan
"It's my strongly held personal position, and I represent three-quarters of the people of Cambridge," he said.
"I've had perfectly civilised conversations (with the Labour leadership). They know my position and they understand exactly why I'm doing what I'm doing and it's for them to decide what to do next."
Shadow home secretary Diane Abbott defended Mr Corbyn's stand on insisting that Labour backs Brexit.
Tulip Siddiq resigned from the shadow ministerial team
She said: "You have to remember how this looks to people in post-industrial Britain, former mining areas, the North, the Midlands, South Wales – it would look as if elites were refusing to listen to them.
"It would be wrong. How could MPs vote for a referendum and then turn around and say 'It went the wrong way so we are ignoring it'?"
Mr Corbyn said he understood the "pressures" facing his MPs, many of whom strongly supported the Remain cause, but urged the party to unite and make sure the legislation goes through the Commons.
Jeremy Corbyn in pictures
Tue, July 12, 2016
Labour Leader Jeremy Corbyn takes part in a community meeting at the Guru Har Rai Gurdwara Sahib temple
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Britain's opposition Labour Party leader Jeremy Corbyn speaks at an anti-racism rally in London
Mr Corbyn said: "Labour is in the almost unique position of having MPs representing constituencies in both directions, and very strongly in both directions.
"I say to everyone, unite around the important issues of jobs, security, economy, rights, justice, those issues, and we will frame that relationship with Europe in the future outside the EU, but in concert with friends, whether those countries are outside or inside the EU."