Tom Watson backed airstrikes against Isil in Syria today, putting himself at odds with Jeremy Corbyn.

Watson said he agrees with the Shadow Foreign Secretary, Hilary Benn, that “there is an imminent terrorist threat being directed from Syria” that requires a military response. And he insisted in a BBC interview that he would not resign from the Shadow Cabinet if Labour MPs were denied a free vote on the issue, as he is “the Deputy Leader of the Labour Party with a mandate.”

Watson’s comment come after Benn made his support for airstrikes clear this morning and sets a sizeable part of the Shadow Cabinet on collision course with Corbyn when it meets again on Monday. It appears impossible that the party will impose a three-line whip against airstrikes, making a free vote almost inevitable.

When the Shadow Cabinet met yesterday, Benn and Watson spoke in favour of military action, along with the Shadow Education Secretary Lucy Powell and Shadow Lord Chancellor, Lord Falconer. Shadow International Development Secretary Diane Abbott, Shadow Communities Secretary Jon Trickett and Shadow Welsh Secretary Nia Griffith joined Corbyn in speaking against.

LabourList understands that Corbyn remains open-minded about a free vote but would prefer the party to agree a common position on military action. Failure to agree one will create confusion over who speaks for the Labour Party from the frontbench when the issue is debated in the Commons later next week.

Whatever the outcome of the Shadow Cabinet meeting on Monday the matter will be re-aired at the meeting of the Parliamentary Labour Party that evening. Corbyn made his opposition to airstrikes clear last night in a letter to Labour MPs. He cancelled a visit to campaign in Oldham today and has not made further comment.