Labour is facing an "existential crisis", the party's deputy leader Tom Watson has warned, after failing to persuade Jeremy Corbyn to stand down.

Mr Watson said the party was heading to a full-blown leadership contest after Mr Corbyn refused even to discuss some form of "negotiated settlement" following Tuesday's unprecedented vote of no confidence by Labour MPs.

While he ruled himself out as a leadership challenger, he said: "This does need solving."

He told the BBC: "My party is in peril, we are facing an existential crisis and I just don't want us to be in this position because I think there are millions of people in this country who need a left-leaning government."

His intervention came after former leaders Ed Miliband and Gordon Brown and former deputy leader Harriet Harman all joined calls for Mr Corbyn to quit while even David Cameron said he should stand down in the national interest.

With speculation that former shadow business secretary Angela Eagle could now stand as a "unity" candidate, a source close to her said reports the she had ruled out a challenge were "absolutely untrue".

"Jeremy Corbyn should do the right thing and stand down," the source told the Press Association. "Angela hasn't ruled herself out of any leadership contest."