Theresa May would be prepared to launch a pre-emptive nuclear strike against the UK's enemies, the Defence Secretary said as he branded Jeremy Corbyn a security risk.
Sir Michael Fallon attacked the Labour leader for calling into question Labour's commitment to the Trident nuclear deterrent, and for suggesting he would be reluctant to authorise a drone strike on the leader of the Islamic State terror group.
The Defence Secretary said the Government could not rule out the use of nuclear weapons in a first strike in "extreme circumstances".
Reed more: Election called before alleged expenses fraud catches up with Tories
Sir Michael used a series of broadcast interviews to criticise Mr Corbyn's approach to defence policy.
On BBC One's Andrew Marr Show on Sunday, Mr Corbyn , who has previously said he would never authorise the use of nuclear weapons, said he stood by his past views on the subject.
"I have made clear my views on nuclear weapons. I have made clear there would be no first use of it. I have made clear that any use of it would be a disaster for the whole world," he said.
Sir Michael said the Government could not rule out ordering a nuclear first strike.
He told the Today programme: "In the most extreme circumstances we have made it very clear that you can't rule out the use of nuclear weapons as a first strike."
Asked about Sir Michael's comments on a pre-emptive strike, the Prime Minister's official spokesman said there was "no reason to disagree with what the Defence Secretary said".
Sir Michael claimed a victory for Labour in the general election would result in "very dangerous chaos".
He told ITV's Good Morning Britain: "I think you saw Jeremy Corbyn yesterday questioning strikes against terrorists, refusing to back the nuclear deterrent, he's been querying our Nato deployment and he seems to have fallen out with his own party over the nuclear deterrent.
"That's chaos, but it's very dangerous chaos that would put the security of our country at risk."
Read more: Independence support fails to rise after Theresa May's vote snub
Labour was forced to restate its commitment to Trident renewal since Mr Corbyn used the Marr interview to say he would order an immediate strategic defence review looking at "all aspects" of defence policy if he was prime minister after June 8.
Echoing a statement from a party spokesman issued after the interview, Labour campaign chairman Andrew Gwynne said renewal of Trident would be in the party's manifesto.
"Yes, it's Labour Party policy. We are committed to renewing the Trident system," he told BBC Radio 4's Today programme.
Sir Michael's comments signalled that the Tories intend to make Mr Corbyn's suitability for high office a key issue in the general election campaign.
But he was unable to stamp out questions over whether Theresa May will recommit to David Cameron's pledge not to put up income tax, VAT or national insurance.
The Defence Secretary left the door open to tax rises, admitting the Tories do not want to commit to too many "prescriptive" targets in its general election manifesto.
Reed more: Election called before alleged expenses fraud catches up with Tories
Shadow defence secretary Nia Griffith said she had made it clear to Mr Corbyn that the party supported the nuclear deterrent.
"It absolutely will be in the manifesto because it's firmly our policy, and that's been reaffirmed time after time," she told BBC Two's Daily Politics.
Challenged on Mr Corbyn's position on authorising a nuclear strike, Ms Griffith said it was "very important that we are absolutely clear that we are prepared to use it".
She said the option of force and the "ultimate deterrent" meant "you are far more likely to actually sustain peace and security at the end of the day".
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here