Several Labour MPs are prepared to vote against the triggering of article 50 in Parliament, despite assurances from the frontbench that the party would not seek to “frustrate” the process.

Labour’s position on the issue caused controversy last week when Jeremy Corbyn appeared to suggest that unless certain conditions were met, he would attempt to block a move to begin the process of the UK leaving the EU. This was quickly contradicted by aides in the leader’s office and shadow Cabinet ministers, including shadow Brexit secretary Sir Keir Starmer, who said that Labour would not seek to “frustrate the process by simply voting down article 50”.

Now it appears that a number of backbenchers could vote against against triggering article 50, even if Labour whips the vote – which could cause problems for some frontbenchers who also wish to vote it down. A number of Labour MPs have told the BBC that their support for backing the process is conditional on various factors.

Tottenham MP David Lammy has long made clear his opposition to moving Brexit, and is joined by Cambridge MP Daniel Zeichner, while a number of others have now laid out what circumstances could lead them to opposing an article 50 bill in Parliament. Shadow Foreign Office minister Catherine West has promised that she “will vote against Brexit in Parliament”.

Helen Hayes, an MP in south London, has said that she backs a second referendum on the terms of Brexit, and will not vote for article 50 unless one is promised. This is a position also held by Owen Smith, who made his views clear on a number of occasions during the leadership contest over the summer.

Hayes told the BBC: “I would not be representing them [her constituents] if I voted to trigger article 50 on the basis of no information from the government about the path that they would then take us on.”

While attempting to block article 50 would be a controversial course of action to take, it could be a popular move among Labour activists, many of whom remain vehement critics of Brexit – especially one led by Theresa May.