Labour leader Jeremy Corbyn has confirmed that he will order his MPs to support the recently published bill granting Prime Minister Theresa May the power to launch Brexit talks.
Corbyn has previously suggested he would "ask" Labour MPs to support the legislation, but he has now gone one step further, making clear that voting against the Bill will be considered an act of rebellion by instituting a "three line whip".
Speaking on Sky News earlier today, Corbyn said: "We want all of our MPs to support the Article 50 vote when it comes up next week. It's clearly a three line whip."
He added: "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 an very strongly in both directions.
"I say to everyone: unite around the important issues of jobs, economy security, rights, those issues , and we will frame that relationship with Europe in the future."
But the Labour leader's decision will rankle with many of his MPs, many of whom have already made clear that they disapprove of the brief window for debate allotted to the Bill, and in particular the "committee stage" at which MPs can seek to amend legislation.
Others, including London MPs David Lammy and Catherine West, have made clear that they will not vote to trigger Article 50 in any circumstance.