Jeremy Corbyn is facing a shadow cabinet rebellion after issuing a three-line whip to Labour MPs over Article 50.
The Labour leader has previously said he will not seek to block the triggering of the EU exit clause - and will now demand his MPs follow suit. A three line whip is the strongest form of voting instruction and tells MPs they must follow the party line.
Mr Corbyn confirmed the decision, saying "It’s clearly a three-line whip. It is a vote on the article 50 ... We will put out a statement today to our members that we want them to vote for article 50.
"I fully understand the pressures and issues that members are under, those who represent leave constituencies and those who represent remain constituencies. 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, economy, security, rights, justice, those issues, and we will frame that relationship with Europe in the future, outside the Europe but in concert with friends, whether those countries are in the EU or outside the EU.
"That’s the message we’re putting out. And I’m asking all of our MPs not to block article 50 but to make sure it goes through."
The decision means several shadow ministers may have to resign in order to vote against their leader. Tulip Siddiq, the early years minister, and Catherine West, part of the foreign office team, have both said that plan to vote against Brexit.
Reports suggest shadow ministers Dawn Butler, Clive Lewis, Jo Stevens and Cat Smith are all considering voting against Article 50 being triggered.
It is unclear how strictly Mr Corbyn's team will enforce the whip - with some Labour sources speculating that there could be some flexibility. Typically any minister or shadow minister who breaks a three-line whip is forced to resign from the frontbench.
A senior Labour source said: "I wouldn't assume anything about the consequences but usual expectations for a three line whip apply."
Reports suggested several members of the shadow cabinet, including Clive Lewis, the Shadow Business Secretary and an ally of Mr Corbyn, had argued against a three-line whip being imposed.
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