Donald Trump has pleaded not guilty to 34 counts of falsifying business records in a Manhattan court – and looked “vulnerable”, a former ambassador has said. But a pollster says the case is “helping” him electorally, and it is now “almost inevitable” he will win the Republican nomination.

Donald Trump is “walking a tightrope” by commenting on the judge presiding over his case, the former UK ambassador to the US has said.

The former president has accused Juan Merchan of being a “Trump hating judge with a Trump hating wife and family” during his speech in Florida after a hearing in New York yesterday.

This was despite Mr Merchan warning him about his use of language and his social media posts when he appeared in court. Speaking to Sky News, Lord Darroch said he thought Trump would “back off” after the judge’s remarks.

In the meantime, the former president’s son, Donald Trump Jr has admitted he signed a check used as evidence by prosecutors in the hush money investigation that resulted in his father’s historic indictment.

President Donald Trump pleaded not guilty to 34 felony counts of falsifying business records as part of Manhattan District Attorney Alvin Bragg’s probe, which focused on a $130,000 sum that Trump’s former attorney Michael Cohen paid adult film star Stormy Daniels to keep an alleged affair she claimed she had with Trump a secret ahead of the 2016 Election.

The actual payment to Daniels is not illegal, but Trump is accused of falsifying business records while reimbursing Cohen for the money, which was listed in Trump Organization records as legal fees. Prosecutors allege the money paid to Cohen was a violation of federal election laws.

Trump has denied having an affair with Daniels.

Speaking to Newsmax’s Greg Kelly in the wake of his father’s arrest on Tuesday, Trump Jr was asked about a part of the indictment, which states that a check from Trump from his own trust was signed by former Trump Organization CFO Allen Weisselberg “and the Defendant’s son, as trustees.”

The indictment adds the check stub falsely recorded the payment as a “retainer” for Cohen.

When asked if he is the son named in the indictment, Trump Jr said: “That son is me. Like I said, clearly also not a campaign finance violation if it’s from his own trust, not to a campaign, not from the campaign, not from the funds raised from it. So, none of it actually makes any sense.”

Trump Jr has not been implicated or accused of any wrongdoing in the case involving his father. Prosecutors would have been aware that Trump Jr was the trustee named in the indictment while writing the legal document.

Falsification of business records is prosecuted as a misdemeanour in New York but can be upgraded to a felony if it is done to conceal another crime.

In this case, that second alleged crime could be a violation of election law if prosecutors maintain that the $130,000 paid to Daniels amounted to an improper campaign donation, arguing that it was used to help Trump’s 2016 election chances by stopping negative stories about his personal life from becoming public.

In 2019, Cohen told a House of Representatives committee that Trump Jr signed some of the checks used to reimburse the attorney for the money he paid Daniels. Legal experts said at the time that Trump Jr would only face prosecution for violating campaign finance laws as part of the case against Cohen if the former president’s son knew what the payments were actually for.

“Weisselberg would probably be the one to say what Don Jr knew or didn’t know when he was signing that check,” Cornell law professor Jens David Ohlin told Reuters at the time.

In 2018, Cohen pleaded guilty to federal tax crimes, including lying to Congress and committing campaign finance violations in relation to the hush money paid to Daniels and former Playboy model Karen McDougal.

Weisselberg, who is currently serving five months in jail after pleading guilty to 15 felony counts relating to a tax evasion scheme carried out by The Trump Organization, also said Trump Jr, as well as his brother Eric, signed checks which Weisselberg then used to defraud tax authorities.

Weisselberg testified during his trial that he did not scheme or conspire with anybody in the Trump family.

“Mr Weisselberg testified under oath that he ‘betrayed’ the trust the company had placed in him and that he, at all times, acted ‘solely’ for his ‘own personal gain’ and out of his ‘own personal greed,'” a spokesperson for The Trump Organization said after the company was found guilty in a separate tax fraud trial in December.

“The notion that a company could be held responsible for an employee’s actions, to benefit themselves, on their own personal tax returns is simply preposterous.”

• A Tell / Sky News /Newsweek report