Zack Polanski said he has been “vindicated” on his position on Donald Trump, who he said had proved himself to be an “increasingly unpredictable and dangerous man”.
The Green Party leader said Sir Keir Starmer was now “saying the exact same things” as him about the US president, despite criticising his position “just a few months ago”.
Speaking at the Green Party’s local election launch in London, Mr Polanski said his party was “heading for a new record-breaking result” at the polls in May.
Answering questions on defence, he said Britain should try to strengthen ties with Europe to bolster defence, arguing the UK is not safe “when our security relies on Donald Trump”.
“I think what we’re seeing in Donald Trump is an increasingly unpredictable and dangerous man,” the Green Party leader said.
“Just a couple of days ago, he said he was willing to wipe out a civilisation.
“Now, thankfully and hopefully, that has been delayed in terms of two weeks of a ceasefire. But the ceasefire we’ve seen, we know that Israel is also taking advantage of in terms of the bombing we’ve seen in Lebanon.”
Adding he now feels “vindicated” on his position, he said: “We had a Labour government who was attacking me for these comments just a few months ago, but are now saying the exact same things.
“It didn’t take a rocket scientist to look at this man and say, this is not someone we can rely on for the security of this country.”
The UK’s relationship with Washington has soured in recent weeks following President Trump’s repeated criticism of Sir Keir Starmer’s response to the conflict.
The US president’s public remarks – which most recently included likening Sir Keir to Neville Chamberlain – have highlighted his increasingly strained relationship and raised questions over Britain’s diplomatic ties to America.
Arguing that Brexit was “one of the most catastrophic decisions this country has ever made,” Mr Polanski renewed calls for Britain to look more to European neighbours and allies for security.
“So I think the time is right now … to be having conversations with our European neighbours, about what does an alliance [and] security look like without relying on Donald Trump. But actually, I think our hand is being increasingly forced on that.”
He added: “I think we generally need to have a huge holistic view at looking at what does our national security look like, because the first principle, rule of any government, and indeed any political leader, should be protecting people in this country.
“And we know we are not safe when our security relies on Donald Trump.”
His comments come after former national security adviser, Lord Peter Ricketts, warned the UK should “completely forget” the idea of a special relationship with the US and can “no longer rely” on Washington as an ally.
Sir Keir declined to say whether his relationship with Mr Trump was ruined on a visit to the Gulf on Wednesday, but defended his guiding “principles” on the Middle East conflict.
Asked whether his relationship with the US president was “in tatters,” the prime minister told broadcasters: “I’ve acted as you would expect of a British prime minister, which is by being absolutely focused on what is our national interest, and that’s why I’ve applied my principles and my values throughout.”
