There's no chance of ousting leader despite differences, declares Labour deputy Tom Watson

The Black Country MP said the left-winger was putting together a "broad based" shadow cabinet and urged moderate colleagues to respect the "huge mandate" provided by his convincing leadership contest win.

But he accepted there were crucial areas - such as the new leader's opposition to the renewal of the Trident nuclear deterrent and his approach to Nato and Europe - where compromise would have to be sought.

Prime Minister David Cameron issued a stark warning that Labour under Mr Corbyn posed "a threat to our national security, our economic security and your family's security".

Mr Corbyn was declared Ed Miliband's successor on Saturday on the back of a surge of support from activists that saw him attract a massive 59.5 per cent of votes.

Mr Watson - appearing on BBC1's Andrew Marr Show yesterday in place of the leader, who pulled out to concentrate on shaping his new team - said he understood the concerns of moderate colleagues about the seismic political shift.

"He wants to build a broad-based party, he wants a front bench that represents all the talents and all the views," the West Bromwich East MP said.

"So I say to colleagues: watch this space, respect the mandate he has been given from our members, try to unify and let's try and get an exciting programme for 2020.

Asked about reports of behind-the-scenes moves to oust Mr Corbyn, he insisted: "There is zero chance of that happening; Labour Party members will not accept that."

In a signal of the potentially divisive battles to come, Mr Watson - seen as a crucial linchpin in securing party unity - accepted that he and many other MPs backed the renewal of Trident.

"There are different views. Nobody wants to live in a nuclear world but it's how you disarm," he said.

"I think the deterrent has kept the peace in the world for half a century and I hope we can have that debate in the party".

He claimed there was no "massive disagreement" on Nato membership - but conceded he didn't know "precisely what Jeremy's position" was and hoped to "convince him of the merits".

"What I have read in the papers is that he actually understands that Nato needs to exist, he respects the views of many party MPs and members on this but he wants to make sure it doesn't expand eastwards.

"These things have got to be worked out."

"I aim to convince him of the merits of Nato. It was created by one of Labour's greatest ever foreign secretaries, Ernest Bevin, because his generation came through the Second World War and wanted to keep the peace."

Mr Watson said he believed the party could present a united front in favour of European Union membership - despite Mr Corbyn failing during the contest to make clear whether he would campaign to stay in at the forthcoming referendum.

"I will be a 'yes to Europe' definitely and I hope we can convince those sceptics in the Labour Party that that is where Labour needs to be in the referendum.

"I hope we can have our own distinct campaign that talks about a social Europe," he added.

Labour backbencher Diane Abbott insisted Mr Corbyn would not take Britain out of the European Union or Nato but told MPs with a "passionate commitment" to nuclear weapons they will be out of step with "the new Labour Party".

Ms Abbott said: "I think they ('moderate' MPs) should stop reading the papers about what Jeremy thinks and ask Jeremy what he thinks.

"Jeremy is not going to take us out of Nato.

"Jeremy is not going to take us out of the EU.

"If they have some passionate commitment in principle to nuclear weapons there may be a difficulty for them with a Jeremy Corbyn leadership.

"But if they have a passionate commitment to nuclear weapons they'll find themselves out of step to the new Labour Party."