Jeremy Corbyn’s attempts to portray Labour as a united government-in-waiting have been blown off course by a bitter civil war over the role of his deputy leader Tom Watson.

The opening of the party’s conference in Brighton was overshadowed by an attempt to oust Mr Watson, who has been a prominent critic of the leader.

The party’s ruling National Executive Committee drew back from an immediate vote on whether to recommend abolishing the position of deputy leader.

But following an intervention by Mr Corbyn the party will review the future of the role.

The Labour leadership also faces a battle over Brexit policy amid claims it is attempting to stifle a bid by members to push for the party to throw its weight behind the Remain cause.

The aborted coup against Mr Watson was condemned in the strongest terms by Labour MPs including former leader Ed Miliband and ex-premier Tony Blair.

Mr Corbyn refused to say when he first knew about the attempt to oust Mr Watson, which began at an NEC meeting on Friday night.

Nor would he say whether he had full confidence in his deputy, instead saying: “Tom Watson is the deputy leader of the party and I enjoy working with him.”

He told reporters: “The NEC agreed this morning that we are going to consult on the future of diversifying the deputy leadership position to reflect the diversity of our society.”

Mr Corbyn claimed there was a “happy and united mood” at the NEC and the conference will be “totally united on defeating this Tory Government”.

Earlier on Saturday Mr Watson had said he was “taken by surprise” at the NEC ambush on Friday night, telling the BBC that it had not been on the agenda and he had sent his apologies to the meeting.

Labour Party Conference
Jeremy Corbyn was challenged over the bid to oust Tom Watson as he arrived at the Brighton conference (Gareth Fuller/PA)

Mr Watson said: “There was no warning.

“I got a text message in a Chinese restaurant in Manchester to say that they were abolishing me.”

Mr Watson had told BBC Radio 4’s Today programme: “It’s a straight sectarian attack on a broad church party.

“And it’s moving us into a different kind of institution where pluralism isn’t tolerated.”

Former leader Mr Miliband said those responsible for trying to oust Mr Watson had “taken leave of their senses”.

Other MPs were not so diplomatic, describing the move as “completely mad” and “totally f****** insane”.

The bid to scrap Mr Watson’s role was led by Jon Lansman, the boss of the Corbyn-supporting Momentum group.

Despite a 17-10 vote in favour of debating the motion on Friday the necessary two-thirds majority to overturn a ruling of the chair that it was not in order was not met and it was postponed until Saturday’s meeting.

After the decision not to proceed on Saturday, Mr Lansman said: “We need to make sure the deputy leader role is properly accountable to the membership while also unifying the party at conference.”

The attempt to remove Mr Watson provoked a furious response from Labour MPs at a time when the conference is meant to put Mr Corbyn’s team firmly on an election footing.

Former minister Yvette Cooper tweeted: “This is completely mad and incredibly destructive.”

Former Cabinet minister Ben Bradshaw said the attempt to “purge” Mr Watson was “totally f****** insane”.

Ex-prime minister Mr Blair said: “A decision to abolish the post of deputy leader would be undemocratic, damaging and politically dangerous.

“To suggest it at this time shows a quite extraordinary level of destructive sectarianism.”

On Brexit, a draft NEC statement suggests the party should go into a general election without specifying whether it would support remaining in the EU at a promised second referendum.

The party would get the issue “sorted one way or another” with a referendum within six months of Labour coming to power.

A decision on how to campaign in that referendum – either for a Labour-negotiated deal with Brussels or to stay in the European Union – would not be taken until a special conference after the general election.

The NEC will discuss the motion again on Sunday and pro-EU activists fear it could be a way of stopping debate on calls by members for the party to back Remain now.

Shadow Treasury minister Clive Lewis said: “This move is just plain wrong. How can this be defended?

“We, the left, took over the leadership of this party promising internal democracy, promising a new kind of politics.

“And yet here we are, with a leadership apparently determined to shut down democratic debate on the crucial issue of the day, probably relying on union bloc votes to outvote the members. It’s not what we signed up for.

“We now need to rally on the conference floor – if it passes, delegates should mobilise to vote against the NEC statement so the Brexit motions can be heard and democratically debated.”