She was expected to announce her candidacy at 3pm, but has delayed standing.

MPs close to her camp say there is a feeling the party needs more time and that the decision is such an important one it cannot be rushed.

Fifty MPs are expected to back Ms Eagle, the former shadow business secretary, triggering a bruising leadership contest that could last months.

However, former shadow work and pensions secretary Owen Smith is also said to be considering a challenge and has reportedly collected nominations from dozens of MPs.

A YouGov poll for The Times suggested that Mr Corbyn might win a leadership contest, but his support had fallen away since May.

The survey, carried out between Monday and Thursday as the embattled leader struggled to maintain his position, found 50 percent of Labour members surveyed would vote for Mr Corbyn but 47 percent would not - down from the 64-33 percent lead in May.

The YouGov poll indicated that Mr Corbyn would beat Ms Eagle by 50 percent to 40 percent if they went head to head.

Despite the mayhem within the Labour ranks in Westminster, 51 percent of the party's members believed Mr Corbyn was doing well, with 48 percent saying he was doing badly.

Some 44 percent said he should step down now as leader of the Labour Party, according to the study, but 60 percent said he should lead the party into the next general election.

The Labour leader’s office is confident they can see off the challenge by recruiting 100,000, £3 temporary members, gaining funding from the unions and deploying supporters from Momentum, the pro-Corbyn activist group.