UK Edition
Labour's divisions over Trident were exposed as the party's defence spokesman clashed with shadow foreign secretary Emily Thornberry over the future of the nuclear deterrent.
Ms Thornberry indicated the party's support for Trident could not be guaranteed after a defence review if Labour wins the June 8 General Election.
But shadow defence secretary Nia Griffith slapped her down, saying the policy was not Ms Thornberry's responsibility and the shadow foreign secretary was wrong.
Ms Griffith said: "With all due respect, Emily is not the shadow defence secretary. I am."
Labour's leadership has said Trident will be covered in a defence review if Jeremy Corbyn - a long-standing campaigner for nuclear disarmament - was in Number 10.
Labour's policy, set by the party conference, supports Trident but shadow foreign secretary Ms Thornberry said she could not guarantee what the outcome of the review would be.
Ms Thornberry, who said she was "sceptical" about Trident, was asked in a radio interview to confirm that backing for the missile system would remain as Labour policy after the review.
She replied: "Well no, of course not, if you are going to have a review, you have to have a review."
On LBC Radio, she said: "Overwhelmingly we need to make sure that our policy is up to date and meets 21st-century threats and no one can disagree with that, surely?
"You know there was a time when we gave up on sabres or horses, you need to keep updating your defence policy and meeting the most pressing and most obvious needs.
"We need to make sure any war that may be fought, will be fought on 21st-century terms."
But Ms Griffith told BBC Two's Newsnight: "We are very clear about the review. When we have the review, coming into government, it is about exactly how we would spend money and what we would be doing and what order we would be doing it, what sort of timetable.
"What it is not about is actually questioning whether we would have a Trident nuclear deterrent because we settled that last year."
Labour's manifesto published on Tuesday included support for the nuclear deterrent.
"Labour supports the renewal of the Trident nuclear deterrent," the document said. "As a nuclear-armed power, our country has a responsibility to fulfil our obligations under the Nuclear Non-Proliferation Treaty. Labour will lead multilateral efforts with international partners and the UN to create a nuclear-free world."
Ms Griffith said: "Nobody has raised the issue of removing the Trident nuclear deterrent from our manifesto."
Asked if Ms Thornberry was wrong, Ms Griffith said: "Indeed. Last year we looked at it, in particular, at the national policy forum and it was decided that we would keep the nuclear deterrent and that was reaffirmed at our conference in September."
Ms Griffith also put distance between herself and Mr Corbyn over the potential use of nuclear weapons and commitment to the Nato principle of mutual defence.
The shadow defence secretary said for the nuclear deterrent to be effective it was necessary that "you are prepared to use it", including a first-strike policy if required.
"You do have to be prepared that might be the circumstances you may find yourself in, in the very uncertain world we live in," she said.
On Nato, Mr Corbyn has said he would not "automatically" send UK troops to support a fellow member which came under attack.
The Labour leader said that the terms of Article 5 of the Nato treaty, which commits member-states to collective self defence, could in some circumstances be fulfilled without the use of military force, by deploying economic and diplomatic pressure.
But Ms Griffith said: "We are fully signed up to Article 5 of the Nato treaty which says, yes, we would put in that defence and yes, we would put in that military force."
There would be diplomatic processes but "ultimately you have to back up your defence and your support" of Nato allies.