BORIS JOHNSON must stop using high office to fund his lavish lifestyle, Labour said today, after it was revealed that the Prime Minister remains under investigation by the Commons sleaze watchdog over a much-criticised Caribbean getaway. 

Parliamentary Commissioner for Standards Kathryn Stone confirmed for the first time today that she is looking into whether the PM properly declared his £15,000 stay at a luxury Mustique hideaway 16 months ago.

Mr Johnson appears on a list of nine MPs now under investigation by the commissioner published under new Commons rules.

In the Register of Members’ Interests, Mr Johnson declared the stay with his fiancee Carrie Symonds as a “benefit in kind” from Carphone Warehouse founder David Ross, who owns a villa on the island.

The disclosure that the commissioner’s inquiry is ongoing comes as the PM continues to face questions over how the refurbishment of his Downing Street flat was paid for.

Labour deputy leader Angela Rayner said: “The public have a right to know who paid for Boris Johnson’s luxury Caribbean holiday and the renovation of his flat.

“Most importantly, we need to know what these donors were promised or expected in return for their generosity.

“As we have seen over the last year, Tory donors have received a very high return on their investment in the form of government contracts.

“Boris Johnson needs to stop using the office of prime minister as an opportunity to fund his lavish lifestyle and enrich his mates.”

A spokesman for Mr Ross said the PM’s Commons declaration was correct.