Office is part-funded by public duty costs allowance, which should only be used to support public work of former PMs

Boris Johnson is under mounting pressure to explain how his private office complies with rules over taxpayer subsidies after further revelations about how his staff appear to be overseeing his global commercial operations.

A leak of data from the Office of Boris Johnson appears to show all three of his staff helping Johnson’s business and profit-making ventures.

The office is partly funded by the public duty costs allowance (PDCA), which rules say should only be used to support the public work of former prime ministers. Johnson said he had followed the rules.

Five other former prime ministers – Tony Blair, Gordon Brown, David Cameron, Theresa May and Liz Truss – have released statements saying they fully comply with rules prohibiting the use of public funds for private business. It is understood Sunak does not claim the allowance.