Jeremy Corbyn would challenge any move to bar him from the Labour leadership ballot paper

The party's NEC will decide whether an incumbent leader is automatically on the ballot paper

Jeremy Corbyn has refused to resign despite a spate of calls for him to go from MPs (Reuters)

Jeremy Corbyn has suggested he will mount a legal challenge to counter any attempt to keep him off the ballot paper in a snap Labour leadership contest.

Labour’s ruling National Executive Committee is due to decide this week whether the party leader must be re-nominated by MPs in order to run in the event of a challenge to his leadership.

The Labour party constitution says that where there is no vacancy for leader, “nominations may be sought by potential challengers”. They require 20 per cent of the party’s MPs to be valid.

The constitution does not explicitly mention whether the leader would be automatically on the ballot paper and conflicting legal opinions have previously been stated on the issue.

Former shadow cabinet minister Angela Eagle has said she will challenge Mr Corbyn for the leadership on Monday – meaning a decision by the NEC will need to be made.

The leader’s low level of support amongst his own MPs would make it difficult for him to secure nominations – but very high levels of support from ordinary party members mean he would stand a good chance of winning if people were allowed to vote for him.

“I’m expecting to be on the ballot paper because the rules of the party say that the existing leader should be on the ballot paper anyway,” Mr Corbyn told BBC One’s Andrew Marr Show.

Ms Eagle will set out her vision 'for the country and the difference a strong Labour Party can make' on Monday (Getty)

He added that he had “not been shown any legal advice” suggesting he would not be on the ballot.

Asked if he would take the issue to court, he replied: “I will challenge that if that is a view they take. I’d just ask anyone in the party to think for a moment: is it really right that the members of the party should be denied a decision, a discussion, a choice in this.

“Half a million people are members of the party because they want the party to succeed. Surely they’re the people who knock on doors, they’re the people that deliver leaflets, they’re the people that raise the money.”

Ms Eagle said this morning that she believe Mr Corbyn “will have to find nominations”.

“I am ready to have a leadership contest and a debate with whoever’s on the ballot,” she told ITV’s Peston on Sunday programme.

April legal advice to Labour from Doughty Street Chambers revealed by Sky News, suggested that, “in absence of express provision or any basis for implying one, I also do not consider that an incumbent require nomination in order to appear on the ballot against a challenger, or to be deemed re-elected in a year in which no challenger emerges.”

That advice described opposing arguments as “weak”. Other legal advice is said to suggest an alternative view.

Mr Corbyn was hit by a spate of resignations from his shadow cabinet last month, with dozens of MPs quitting and calling for him to step down. He has refused to resign, however.