A businessman accused of being a Chinese spy was invited to Buckingham Palace and other royal residences by the Duke of York, it has been reported.

The man – who was banned from Britain by the government on national security grounds – visited Buckingham Palace twice, and also entered St James’s Palace and Windsor Castle at the invitation of Andrew, the Times reported.

On Friday, the duke said he had “ceased all contact” with the businessman when concerns were first raised about him. A statement from his office said Andrew met the individual through “official channels”, with “nothing of a sensitive nature ever discussed”.

Last March, the businessman, only known as H6, brought a case to the Special Immigration Appeals Commission (Siac) after the then home secretary, Suella Braverman, said he should be excluded from the UK in March 2023.

Judges were told that in a briefing for the home secretary in July 2023, officials claimed H6 had been in a position to generate relationships between prominent UK figures and senior Chinese officials “that could be leveraged for political interference purposes”.

Rana Mitter, the ST Lee professor of US-Asia relations at the Harvard Kennedy School and an expert in Chinese politics, told BBC Radio 4’s Today programme that part of the Chinese spying strategy was to look for people who might be “influential over time” but are “in a bit of a doldrums”.

He said the situation involving the Duke of York and H6 is “not so much about spying in the sense of trying to find out secrets, it’s about trying to influence”.

“Getting to know the elites of countries like Britain is a useful task, not for immediate knowledge but maybe for long-term development of links in society. It seems that’s what has been going on here,” Mitter said.

“One of the things that quite often will happen is looking out for who may be influential over time, but perhaps is in a bit of a down spot, a bit of a doldrums.

“One of the best examples from a generation ago would have been President Richard Nixon – after he had to resign in disgrace over Watergate he was frequently invited to China.”

Several newspapers have reported that the king has been briefed about his brother’s links to the alleged spy.

The revelations come after the royal family reportedly took further steps over the summer to distance themselves from the disgraced duke, with the king said to have axed his £1m annual “living allowance” and the security Charles had been privately funding for Andrew’s home.

Andrew Lownie, who is writing a biography of the duke and Sarah, Duchess of York, said the latest news involving the king’s younger brother would affect the wider family and the “future of the monarchy” as he called for greater transparency around the the royals’ finances.

He said: “The real scandals surrounding him are financial more than sexual.

“Given he cannot police his own activities and understand where the moral boundaries lie, it is time for proper scrutiny of his finances and a public register of royal interests.

“Judging from online comments to newspaper articles, this episode is highly damaging for the whole of the royal family, whose finances and business activities should now be more transparent.”

Senior Tories including Braverman have called for H6 to lose his anonymity, as a “deterrent to others taking part in similar activities”.

Speaking from Italy on Saturday, the home secretary, Yvette Cooper, said: “Our security and intelligence agencies are continually vigilant for any threat to UK national security, whether that be around foreign influence, whether it be around espionage, whether it be around any security threat.

“We won’t hesitate to take action wherever any challenge arises.”

Asked whether the anonymity of H6 should be lifted, she said: “We always respect the decisions of the courts and also don’t comment on individual cases.”

Buckingham Palace and the Duke of York’s office have been approached for comment.