John McDonnell has insisted Jeremy Corbyn is "not going anywhere" despite the prospect of a shadow cabinet revolt.
Hilary Benn was sacked from the position of Shadow foreign secretary by Corbyn in the early hours of Sunday morning while the shadow health secretary Heidi Alexander resigned shortly before 9am.
The shadow chancellor was asked on the BBC's Sunday Politics programme if the shadow cabinet turmoil will lead to Corbyn being replaced as Labour leader.
He said: "No, not at all, not at all. Jeremy's not going anywhere.
"He was elected nine months ago, the biggest mandate of any political leader in our country, and he is not going anywhere.
"The people who are sovereign in our party are the members.
"It's the members who elected Jeremy and he will remain."
The shadow chancellor, in a message to shadow cabinet colleagues, said: "I know how disappointed people are at the loss of the European referendum, but now is the time that we hold together - there is no government in place. We have got to provide that leadership."
Corbyn won the Labour leadership with massive support from the party's membership and McDonnell warned would-be rebels to listen to the grassroots.
"Listen to your party members who voted for Jeremy in overwhelming numbers nine months ago - hang together. That principle of Labour solidarity is key at this point in time."
McDonnell, who has run for the leadership before as the Left's candidate, said: "I will never stand for the leadership of the Labour Party.
"If Jeremy has to stand for another leadership election, I will chair his campaign and I think the Labour Party members will elect him again."
Shadow transport secretary Lilian Greenwood is rumoured to be among the shadow cabinet ministers set to resign, while shadow Scottish secretary Ian Murray - who has previously voiced concerns about Corbyn - is also reported to be on the brink of quitting.
Amid speculation that a full-blown coup was being organised against Corbyn, Benn indicated that members of the shadow cabinet had been talking to each other about the situation.
He told BBC One's Andrew Marr Show: "At this absolutely critical time for our country, following the EU referendum result, the Labour Party needs strong and effective leadership as we take decisions of huge importance for the future of our country.
"We don't currently have that and there is also no confidence that we will be able to win a general election as long as Jeremy remains leader."
Asked if there would be further resignations, Benn said: "Of course members of the shadow cabinet, as you would expect - certainly in the wake of the referendum result - have been talking to each other.
"It is for each individual to make their own decision, I have made mine and I made my views clear to Jeremy.
"He is a good and decent man but he is not a leader and that is the problem."