Boris Johnson has dismissed Donald Trump’s conviction as the result of a liberal “hit job” that would only make his re-election more likely.

The former prime minister, who enjoyed warm relations with the then president while in office, said: “This was no ordinary political assassination. This was a machine-gun mob-style hit-job on Trump.”

But he said the “anti-Trump lawfare is backfiring”, and has “helped to make his victory more likely, not less” in his rematch with Joe Biden.

On Thursday, a New York jury found Trump guilty on all 34 counts of falsifying business records to buy the silence of Stormy Daniels, an adult film star.

Mr Johnson is the most high-profile British politician to back Trump so far, piling pressure on Rishi Sunak and Sir Keir Starmer to do the same to safeguard the special relationship between the US and UK.

The two men sought to avoid expressing an opinion on the case while on the campaign trail on Friday. Whoever is Prime Minister following the general election faces having to work with Mr Trump if he triumphs in the US election in November.

Appearing at a press conference in New York on Friday, Trump said the “corrupt” trial proved America had become a “fascist state” and he vowed to appeal the verdict that had made him the first convicted felon former president.

Mr Johnson backed the Republican 2024 nominee in his column for the Daily Mail. He wrote: “The vast mass of American voters could see what I believe was really happening: that the liberal elites were just appalled at Trump’s continuing popularity and his ability to connect with voters – and they were using anything they could find to derail his campaign.”

Earlier in the day, Mr Sunak had refused to discuss the outcome while out campaigning.

“You wouldn’t expect me to comment on another country’s domestic politics or judicial processes,” the Prime Minister said.

On Friday evening, Mr Sunak went further, saying: “What I would say is the US has always been a key partner and ally of the United Kingdom. I’ve always had a good relationship with my opposite number, any British prime minister should prioritise that.”

He added: “Of course I respect the justice system of the United States.”

Sir Keir, a former director of public prosecutions, also said he “respects the court’s decision”.

However, the Labour leader insisted the conviction would not change the party’s recent charm offensive with the Trump campaign.

Should Labour win the general election on July 4, he said: “We will work with whoever is elected president … but it is an unprecedented situation, there is no doubt about that.”

A source on the Conservative campaign said: “It’s much more of a problem for [Labour] than it is for us.

“There is a danger for Keir Starmer that he is just going to be constantly asked to condemn what one of his candidates has said about Trump.”

Mr Biden condemned his opponent on Friday night in his first direct comments on the conviction.

“It’s reckless, it’s dangerous, it’s irresponsible, for anyone to say this was rigged, just because they don’t like the verdict,” the US president said.

Trump’s conviction does not disqualify him from seeking the White House or occupying it should he beat Mr Biden, 81, in November’s presidential race.

The 77-year-old blamed the president and the “devil” judge overseeing his hush money trial for his conviction in his rambling speech from Trump Tower, the site of his victorious 2016 campaign launch.

The former president warned that, if he could be convicted, “it can happen to anyone”.

Describing the presiding judge, Juan Merchan, he said: “He looks like an angel, but he’s really a devil.”

Mr Merchan will sentence Trump on July 11, just days before the Republican national convention, where his party is set to crown him as the GOP presidential candidate.

Trump faces a maximum penalty of four year imprisonment, but experts agree a custodial sentence for the former, and possibly future president, is unlikely.

If Trump were to get a prison term, his secret service protection officers would be required to guard him in jail.

More lenient punishments include probation or a fine.

Any punishment could be delayed until after Trump’s appeal process, which could run far beyond election day on Nov 5.

It came as Trump claimed to have raised $39 million, largely from small-dollar donors, since his conviction. He argued that the vast sum had been matched by a bump in the polls, which previously had him level-pegging with Mr Biden, and was proof Americans saw that his guilty verdict went “far beyond me”.

“This is bigger than Trump. This is bigger than me, this is bigger than my presidency,” he said.

Senior Republicans in Congress have rallied behind their presidential candidate, including Mitch McConnell, the GOP Senate leader, who has endured a frosty relationship with Trump.

Mr McConnell said the charges against him “never should have been brought” and he expected them to be “overturned on appeal”.

Writing in the Daily Mail, however, Mr Johnson said: “The vast mass of American voters could see what I believe ...  that the liberal elites...  were using anything they could find to derail his campaign.”

Mr Johnson repeated his endorsement of Mr Trump in the 2024 race, saying: “Whatever his detractors may say, I believe that Donald Trump – at his best – could offer the world the strong, confident leadership that it needs.”