When Donald Trump rose to address the prestigious Gridiron Club dinner earlier this month, he apologised for being late.

“Jared could not get through security,” he explained.

The joke was one of a series of light-hearted barbs targeting members of his administration. But for Mr Trump’s son-in-law, Jared Kushner, it may have cut a little too close to the bone.

Barely a week previously, John Kelly, the president’s chief of staff, ordered Mr Kushner be stripped of his interim top secret security clearance. While the move was part of a wider crackdown on White House staff whose access to classified material has still not been made permanent by the FBI, Mr Kushner was its most high-profile victim.

The president’s son-in-law is a senior adviser with multiple responsibilities including the administration’s much-awaited Middle East peace plan.

Publicly, Mr Kushner has attempted to project an image of business as usual. Last week, he held talks in Washington with Benjamin Netanyahu before the Israeli prime minister visited the Oval Office to meet the president.

However, over the past fortnight, he has been hit by a series of damaging public revelations which have fuelled speculation that he may be the next departure from a chaotic White House which is haemorrhaging senior staff.

The Washington Post reported earlier this month that officials in at least four countries – including Israel, the United Arab Emirates, Mexico and China – had privately discussed ways to manipulate him.

Each supposedly considered him a potential target due to his lack of government experience and the Kushner family’s complex business dealings and debts.

In a separate but related development, the New York Times then alleged that Apollo, a private equity firm, and Citigroup loaned more than $500 million (£357 million) to the family’s property business after senior executives of the companies attended White House meetings with Mr Kushner. Mr Kushner denies any wrongdoing.

These developments came as Special Counsel Robert Mueller’s investigation into Russian meddling in the 2016 presidential election continued to gather pace.

Mr Kushner’s contacts with Kremlin-linked individuals during the campaign and transition are said to be part of the probe, with some West Wing staff reportedly reluctant to have conversations with Mr Kushner or in his company because they are unsure if he’s a witness or a target of Mr Mueller.

Mr Kushner’s lawyer says he is not under suspicion.

Internally, Mr Kushner lost an ally with the resignation of Gary Cohn, Mr Trump’s chief economic adviser, over the president’s plan to impose tariffs on aluminium and steel imports.

Stephen Miller, the former Goldman Sachs chief executive, and Mr Kushner are the most senior Jews in the administration. But while Mr Miller is a hardline conservative, Mr Cohn and Mr Kushner are centrists on issues such as immigration and trade who have tried to exercise a moderating influence on Mr Trump.

Mr Cohn is believed to have come close to quitting last summer after the president failed to unequivocally condemn the white supremacists who marched through Charlottesville, and publicly distanced himself from his boss.

Other friends also appear to be peeling away from Mr Kushner. Last week, the Wall Street Journal strongly hinted that he should consider his position in the White House. The paper’s owner, Rupert Murdoch, has long been close to Mr Kushner and his wife, Ivanka.

It is, however, Mr Trump who will ultimately decide Mr Kushner’s fate. Publicly he has berated his “unfair treatment” and called him a “high-quality person”.

However, Mr Trump has reportedly also discussed ways of moving the couple out with Mr Kelly, who himself is no fan of the informal power exercised by the president’s daughter and son-in-law.

Mr Trump’s disloyalty to those who work for him is legendary, but he is always believed to have been fiercely protective of his family. Like much else about the president, that may turn out to be untrue.