There have been suggestions that the Russian president could carry out such a military coup as his forces continue to lose territory they seized earlier in the invasion. But in his first interview since leaving Number 10 for Sky News’ program Ukraine: A Modern War, the former prime minister told Sky’s Mark Austin: “I don’t think he will, he’d be crazy to do it.” . Mr Johnson also said he would travel to the COP27 climate summit in Egypt next week, as questions remain over whether Rishi Sunak will attend. Putin’s hands ‘may prove to be up to no good’ – Ukraine war live updates Johnson said the use of a nuclear weapon would mean Putin would “immediately submit 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 put into a “cryogenic economic freeze” and Mr Putin would “lose a lot of the middle ground of global tacit consensus that he had”. Referring to sub-Saharan Africa, Latin America and South Asia, Mr Johnson said: “There is a great willingness to give Putin the benefit of the doubt. That will go, the moment he does something like that. “He would also crucially lose the protection of the Chinese. And in his own country, I think he would set off an absolutely hysterical reaction.” You can watch the full interview on Ukraine: A Modern War on Sky News from 7.30pm tonight Johnson said that if there was such a military action by Mr Putin, there would have to be some response. “There are all kinds of options” in both NATO and the P3 states (US, UK and France), he said. Use Chrome browser for more accessible video player 3:22 What is a tactical nuclear weapon? But he added that he thought it was “very, very, very, very unlikely that it would come to that (a tactical nuclear attack by Putin)”. He also said it was a “critical” and “pivotal moment” for the world. Looking ahead to how the conflict could be resolved, the former prime minister warned of the danger of trying to “make and find some kind of deal, some scandalous bargain with Putin” by trying to encourage Ukrainians to trade part of their territory , which Mr Johnson said would “only encourage Putin to do further aggression”. Use Chrome browser for more accessible video player 1:52 Putin’s only goal is to ‘spread terror’ He said it would be very difficult for Ukrainians to accept any deal that stopped short of the full return of all areas seized by Russia since the invasion began on February 24. Mr Johnson also said it was “absolutely inevitable” that the Ukrainians would eventually win the war. “We have to show strategic patience and continue to support them,” he added.