ERIC TRUMP MUST testify in a New York investigation into the family’s businesses before the November presidential election, a judge has ruled.

State Judge Arthur Engoron said that President Donald Trump’s son must comply with a subpoena for his testimony no later than 7 October, adding that the investigation and the court are not “bound by the timelines of the national election”.

Attorney General Letitia James, a Democrat, went to court to enforce the subpoena after Eric Trump’s lawyers abruptly cancelled a July interview with investigators in a probe about whether the family’s company, the Trump Organisation, lied about the value of its assets in order to get loans or tax benefits.

Eric Trump, the company’s executive vice president of development and acquisitions, was first served with the subpoena in May.

In a court filing last week, his lawyers said he was willing to comply with the subpoena, but only after the 3 November election. Beside scheduling conflicts related to his father’s re-election campaign, they said they wanted “to avoid the use of his deposition attendance for political purposes”.

At today’s hearing, Eric Trump’s lawyer Alan Futerfas said they were “happy for him to sit down and be deposed”, but that they needed more time before he testifies to review with him thousands of pages of documents that James’ office is seeking as part of the civil probe.

“As the world knows, there’s an election going on in about four weeks in this country, maybe five weeks,” Futerfas argued. “Eric Trump is a vital and integral part of that, and he’s traveling just about seven days a week.”

Matthew Colangelo, a lawyer for the attorney general’s office, countered that Eric Trump’s lawyers did not have a legal basis to seek a delay and were doing so “simply on the grounds of personal inconvenience to the witness”.

He argued that the typical compliance deadline courts have found is reasonable is five days.

Eric Trump’s lawyers had proposed four dates for him to testify, the earliest being 19 November, which they contended is just after James’ office is scheduled to interview other witnesses in the investigation.

Eric Trump switched lawyers in mid-July, Futerfas said, contributing to the need for a delay.

Eric Trump did not participate in today’s hearing, which was held via Skype.

Ms James went to court to compel Eric Trump and other business associates to testify and turn over documents as part of a civil investigation into whether the family’s company, the Trump Organisation, lied about the value of assets including a suburban New York City estate and a Los Angeles golf club.

Investigators have yet to determine whether any law was broken, James’ office has said.

James launched her civil investigation of potential fraud in Donald Trump’s business dealings in March 2019 after long-time personal lawyer Michael Cohen told Congress that the president had repeatedly inflated the value of his assets to obtain more favourable terms for loans and insurance coverage.

James’ investigators are looking into how the Trump Organisation and its agents assessed the value of Seven Springs, a 212-acre estate north of New York City that Mr Trump purchased in 1995 with the intent of turning it into a golf club.

The attorney general’s office is also attempting to collect information about the Trump National Golf Club near Los Angeles, where the Trump Organisation donated a conservation easement over part of the property in 2014 and received a tax deduction.

And investigators said they were also probing the circumstances of how the Trump Organisation handled tax issues related to more than 100 million dollars of debt related to the Trump International Hotel and Tower Chicago that was forgiven between 2010 and 2012.

Investigators said they have not been able to confirm whether any of that forgiven debt was recognised as taxable income, according to the court filings.