Jeremy Corbyn has conceded he would have to "live with" Labour support for nuclear weapons if he failed to persuade the party to adopt his stance on unilateral disarmament after a backlash from senior MPs.
The Labour leader, who provoked a fresh row over the nuclear issue by saying he would never press the button to launch a strike if he was prime minister, accepted he would be prepared to back down over one of his main political principles if he could not convince his party to agree with him.
Mr Corbyn, who said he could "obviously" imagine being in Number 10, had previously stressed he has a mandate from party members for his opposition to renewing the Trident nuclear deterrent.
But his comments about what he would do if he had control of the nuclear button were described as unhelpful by shadow defence secretary Maria Eagle, who said they "undermined to some degree" the review she was carrying out of the party's defence policy, while shadow foreign secretary Hilary Benn said the prime minister "has to have the option" of launching a nuclear strike.
Ms Eagle told the BBC that Labour's current policy was in favour of retaining a nuclear deterrent, adding: "I don't think that a potential prime minister answering a question like that, in the way in which he did, is helpful."
Mr Benn told BBC Radio 4's World at One: "Jeremy's got his longstanding view but the view of the party conference over many years and it's been reaffirmed here in Brighton is that we believe in maintaining our independent nuclear deterrent.
"And I would say that any prime minister has to have the option because that is the whole theory on which deterrence is based."
Responding to Ms Eagle's comment, Mr Corbyn told reporters: "We will be having a discussion and a debate about nuclear weapons.
"We are going to have discussion and a debate about how we fulfil our obligations under the Nuclear Non-Proliferation Treaty and we will go forward from there.
"There's no decision required until probably next summer on this.
"I hold a view which is well known on nuclear weapons and it is a view which I have held all my life."
Asked whether he stood by his statement that he would not use nuclear weapons as PM, he replied: "Would anybody press the nuclear button?"
He added: "Nuclear weapons are weapons of mass destruction that take out millions of civilians.
"They didn't do the USA much good on 9/11.
"The problems of this world are not huge wars in that way, the problems are much more from fairly random acts of terrorism."
Speaking on BBC Radio 4's Today programme, Mr Corbyn said "we are not in the era of the Cold War any more" as he defended his stance on Trident but insisted Labour was not a "divided party".
He said: "There are five declared nuclear weapon states in the world.
"There are three others that have nuclear weapons.
"That is eight countries out of 192."
Asked if he would use nuclear weapons if he was in Downing Street, he said: "No. 187 countries don't feel the need to have a nuclear weapon to protect their security, why should those five need it themselves?
"We are not in the era of the Cold War any more.
"I am opposed to the use of nuclear weapons, I am opposed to the holding of nuclear weapons.
"I want to see a nuclear-free world.
"I believe it is possible."
In an interview with ITV News he said :"If I can persuade the whole of the Labour Party to come round to my point of view, I would be very, very happy indeed.
"I will do my best."
But, he added: "If I can't, we'll live with it somehow."