Boris Johnson has told Sky News he does not believe Vladimir Putin will use a tactical nuclear weapon in his war in Ukraine.
It has been suggested that the Russian president could carry out such a military strike as his forces continue to lose territory they captured earlier during the invasion.
But in an exclusive interview for Sky News Ukraine: A Modern Warfare Programthe ex-Prime Minister told Sky’s Mark Austin: ‘I don’t think he will, he would be mad to do it.’
Mr Johnson also said he will travel to the COP27 climate summit in Egypt next weekas question marks remain over whether Rishi Sunak will join him.
Putin’s hands ‘could prove he’s not okay’ – Ukraine war live updates
Mr Johnson said that the use of a nuclear weapon would mean Mr Putin “would immediately present Russia’s resignation from the club of civilized nations”.
The former UK leader said it would be a ‘total disaster’ for Russia, which would be placed in a ‘cryogenic economic freeze’ and that Mr Putin would ‘lose much of the common ground of global tacit acquiescence that he had”.
Mentioning sub-Saharan Africa, Latin America and South Asia, Mr Johnson said: “There’s a lot of willingness to give Putin the benefit of the doubt. It will be fine, as soon as he does something like that.
“He would also crucially lose Chinese patronage. And in his own country, I think he would trigger an absolutely hysterical reaction.”
You can watch the full interview on Ukraine: A Modern War on Sky News from 7.30pm tonight
Mr Johnson said if there was such a military act by Mr Putin there should be some response.
“There are all sorts of options” both in NATO and in P3 countries (US, UK and France), he said.
But he added that he thought it was “very, very, very, very unlikely that it would come to this (a tactical nuclear attack by Putin)”.
He also said it was a “critical” and “pivotal” moment for the world.
Looking forward to how the conflict might be resolved, the former prime minister warned of the danger of trying to “understand and find some sort of deal, a dirty deal with Putin”, trying to encourage Ukrainians to swap some of their territory, which Mr Johnson said ‘will only encourage Putin to do more aggression’.
He said it will be very difficult for the Ukrainians to agree to a deal that stops short of a full return of all areas taken by Russia since the start of the invasion on February 24.
Mr Johnson also said it was ‘absolutely inevitable’ that the Ukrainians would eventually win the war.
“We need to be strategically patient and continue to support them,” he added.