Former members of Corbyn's shadow cabinet have questioned whether he should be allowed to stand in a new leadership contest
The leader of the UK Labour Party Jeremy Corbyn has said he is "disappointed" that Angela Eagle is launching a leadership campaign against him.
Mr Corbyn called on the former shadow business secretary, who quit his frontbench team in protest, to "think for a moment" before mounting her challenge.
The veteran left-winger also revealed he had taken "soundings" from lawyers and he expected to be on the ballot as the sitting leader, although this has been disputed by opponents.
Mr Corbyn insisted: "The rules in my view are absolutely clear."
He said he would be prepared to mount a legal challenge if he was left off the leadership slate.
Arguing he had been given a large mandate by Labour members, Mr Corbyn added: "I think we are a party that's going places and doing very well."
He pointed out under him the party's membership had grown to more than 500,000 people, won elections and delivered more than 20 defeats to the Government at Westminster.
Despite the party turmoil, Mr Corbyn insisted: "There's no wobbles, there's no stress, there's no depression."
But Ms Eagle said of Mr Corbyn: "He's not a bad man, he's not a leader though."
Speaking to ITV, she said: "He doesn't connect with Labour voters. He doesn't connect enough to win an election and he doesn't reach out in any meaningful way to other parts of the party.
"He's lost the confidence of his parliamentary colleagues.
"He's hiding behind a closed door, denying that this is a fact. That's not leadership."
Asked if Mr Corbyn should be allowed to stand in a new leadership contest, she said it was a decision for Labour's ruling National Executive Committee, but pointed out it was party precedent for candidates to secure more than 50 nominations.
Ms Eagle said: "This is not about splitting the Labour Party this is about uniting the party."
Lord Falconer, who resigned as shadow justice secretary, told Sky News that Mr Corbyn should not automatically qualify for the leadership race.
"If he can't get 51 MPs to back him what does that tell you?" he said.
He added: "The position is that Labour is voiceless. That, at a time when the country rightly is saying we need some degree of leadership form our political leaders."
But shadow education secretary Angela Rayner said Mr Corbyn had received a "significant" mandate less than 12 months ago to lead the party.
Urging her parliamentary colleagues to come together to hold the Government to account, Ms Rayner said: "We need an effective opposition at this time."
Meanwhile, former shadow work and pensions secretary Owen Smith, who is also thought to be considering a leadership bid, said: "I am not prepared to stand by and see our party split.
"And I have asked to meet with Jeremy again tomorrow to see how we can stop that."