Ken Livingstone, the former mayor of London who was suspended from Labour over comments about Hitler supporting Zionism, has said he will apply to join the Green party. Describing himself as “both green and red”, he told the Guardian: “I genuinely think we’re heading toward extinction before the end of the century because no government anywhere is doing enough to tackle the impact of climate change. “At Cop26 they all said the right things but … you’ve got to get people to completely change the way we live and no government around the world seems to have the courage to do that.” During his time in office, the 76-year-old once known as “Red Ken” launched environmental measures such as the congestion charge. He also founded the C40 group of mayors for cutting emissions, which was backed by figures such as Bill Clinton, Al Gore and the then UN climate chief, Christiana Figueres. But Livingstone was a polarising and controversial figure, leaving the Labour party after he was suspended in May 2016 for telling a journalist that when Hitler was first elected, “he was supporting Zionism before he went mad and ended up killing 6 million Jews”. Livingstone said he was alluding to the contentious 1933 Haavara agreement between Nazi Germany and some Zionist groups. The Haavara deal undermined an attempted Jewish boycott of Nazi Germany, but enabled about 60,000 Jews to migrate to Palestine, if they used their assets to purchase exported German goods. To critics, though, his words trivialised the genocide, confused its agency – which belongs solely to Hitler – unfairly linked Zionism and nazism and even offered Hitler a “diminished responsibility” defence. Zack Polanski, a Green party London assembly member, said: “The rules are very clear that there’s no space in the party for antisemitism, transphobia, racism, sexism or any other form of discrimination and while it wouldn’t be appropriate to comment on any individual application, I’d expect any new member – whoever they are – to follow our code of conduct.” Membership applications from high-profile political defectors first have to go to a Green regional council for an internal consultation process. Asked whether they would accept Livingstone as a member, a party spokesperson said: “We welcome everybody who shares our political aims and values to join the Green party.” Livingstone still denies having misspoken on Zionism but added that “if I’d known it was all going to be distorted like this, I would of course have done a much longer, boring analysis about the history”. He first put out feelers to the Greens in talks with several senior members that covered “how much I wanted to join and what I’d do”, he said, “but they never got back to me”. His initial suspicion had been that they “thought that if they brought me in they’d be accused of being antisemitic”, he said. His message to the party now, though, was straightforward: “Have me in!” he said. “I never met anyone in the Green party I didn’t like. I will apply to join them [the Greens].” Issues such as air pollution controls, bike lanes and green job guarantees for rust-belt workers were ripe for campaigning work, he said. “I would like to see a Green-Labour coalition run the country,” he said. But he advised socialists to stay in the Labour party to help build such an alliance, which has some precedents. In 2008, the Greens called for their supporters to transfer their second votes to Livingstone in the mayoral vote eventually won by Boris Johnson. The Green peer Jenny Jones, Livingstone’s former deputy, was more effusive. Ken was “incredibly green”, she said and “understood the climate emergency”. She added that she had seen no evidence of antisemitism by him in eight years of working together. “As far as I’m concerned, I would welcome him,” she said. “He was a superb mayor and he was followed by Boris Johnson, who doesn’t understand the environment and is obsessed by economic growth.” While maintaining that Keir Starmer “will be the best prime minister since Clement Attlee”, Livingstone did not rule out a run for mayor as a Green candidate. “I will be 78 or 79 by the time of the next mayoral election and I don’t think people will be rushing to vote for someone that old,” he said. “But I would love to do it.” • This article was amended on 17 January 2022. The 1933 Haavara deal enabled Jews to migrate from Nazi Germany to Palestine, not Israel as stated in an earlier version.