Is that the PM asleep in the bridal suite at a York hotel?

A barefoot man said to be David Cameron is pictured on a four-poster before the wedding of his sister-in-law Alice Sheffield two weeks ago.

The photo was posted on the Instagram website by the bride’s half-sister Emily Sheffield, who is sister to the Prime Minister’s wife Samantha Cameron.

It has since been removed but has appeared subsequently on other websites where it has attracted an audience estimated to number tens of thousands.

The Prime Minister had just returned from the G20 summit in St Petersburg at the time the photograph was taken.

He accompanied his wife to Miss Sheffield’s wedding to French estate agent Etienne Cadestin at Sutton-on-the-Forest Parish Church near York.

According to reports, the red government dispatch box in the photograph is the one Mr Cameron left unattended on a train from London to York earlier the same day.

Passengers took photographs of the box, with the key still in the lock, while Mr Cameron visited the buffet car. Downing Street later insisted it was being watched by security officers.

Alice Sheffield once worked for Mr Cameron as a correspondence secretary and is the founder of the cosmetics website Bare Faced Cheek.

After the wedding, Mr Cameron, who is said to favour afternoon “power naps”, was photographed with the bride and groom.