The Conservatives are calling for Sir Keir Starmer to face a standards probe over the appointment of Labour donor David Kogan as England’s new football watchdog.

Culture Secretary Lisa Nandy was found to have “unknowingly” breached public appointment rules by not declaring Mr Kogan’s donations to her 2020 Labour leadership campaign before picking him for the job.

The Tories are arguing that the prime minister had “exactly the same conflict of interest” since Mr Kogan had also donated to the prime minister’s Labour leadership campaign.

Downing Street dismissed the calls, saying an extensive review by the Independent Commissioner for Public Appointments found no further breaches.

Nandy announced Mr Kogan, a sports rights executive, as the government’s preferred candidate to chair the football regulator in April.

But she stepped back from the appointment process the following month, after he revealed to MPs that he had given “very small sums” to her 2020 Labour leadership campaign, as well as that of the now prime minister.

In a report published on Thursday, the commissioner for public appointments, Sir William Shawcross, revealed Mr Kogan had made two donations of £1,450 each to Nandy’s campaign, one personally and one through his company.

They were part of total donations worth £33,410 to Labour and the party’s candidates in the five years prior to his appointment, the commissioner said.

The two donations to Nandy’s campaign were below declaration thresholds set by the Electoral Commission and by Parliament.

But Nandy should have checked if the sports agent had contributed before endorsing him, Sir William said, and taken “any necessary consequential action”.

“The fact of the donations was capable of giving rise to a perceived conflict of interest in the appointment process,” he added.

Nandy apologised on Thursday, telling the prime minister in a letter: “I deeply regret this error. I appreciate the perception it could create”.

Sir Keir has stood by his culture secretary, telling her in reply that she had “acted in good faith”, and he “noted the commissioner’s findings that the error was unknowing”.

The commissioner did not specify how much money Mr Kogan donated to Sir Keir’s 2020 campaign. Electoral transparency records show he separately donated £2,500 to Sir Keir’s local Labour branch in May last year.

Nandy was the “formal appointing authority” for the regulator role, but it is listed by the government as one in which the prime minister has a “strong interest”

According to Sir William’s report, Mr Kogan’s appointment was “cleared” by 10 Downing Street, having been sent for “final approval”.

The Conservatives have now asked Sir Laurie Magnus, Sir Keir’s ethics adviser, to investigate whether the prime minister’s role in Mr Kogan’s appointment, and his verdict on Nandy’s role, broke ministerial rules on transparency.

In a letter to Sir Laurie, shadow Cabinet Office minster Alex Burghart wrote: “If Ms Nandy recused herself from involvement in this appointment, shouldn’t the prime minister have done the same?

“Isn’t the prime minister complicit in exactly the same conflict of interest?”

Mr Kogan was longlisted for the role under the previous Conservative government but the process was paused after last year’s general election was called, according to Sir William’s report.

The commissioner added that Mr Kogan initially withdrew his application in November last year, before eventually being re-selected for the role as an external candidate.

In a statement on Thursday, Mr Kogan said: “I have cooperated fully throughout the investigation and can now draw a line under the process.

“As the commissioner states, my suitability for the role has never been in question, and at no point was I aware of any deviation from best practice.

“It is now time to move on and get on with the business of setting up the IFR [Independent Football Regulator] so we can tackle the critical and urgent issues facing football.”

A Government spokesperson said: “The Chair of the Football regulator was appointed by Ministers in the Department for Culture, Media, and Sports, as set out in the legislation.

“This was the case under the previous Government.

“The Independent Commissioner for Public Appointments reviewed the appointment process extensively and found no breaches aside from those set out in the report.”