His friend Boris Johnson, who was elected mayor two months ago, first advocated the use of sharia law last year after having his bicycle stolen outside London’s Euston station.

Whether he wanted the thieves stoned to death or just their hands cut off was not clear.

Mr Cameron confirmed he had reported Wednesday’s theft to police but was not “holding his breath” for the bike’s return – some 20,000 are stolen in London every year. He said: “If anyone has seen it, I would very much like it back. To me it was absolutely priceless.

“I was cycling home and stopped to pick up some things for supper. I chained the bike through the wheel and put it around one of those bollard things.

“I have reported it using the police’s new online facility but I’m not expecting to get it back any time soon.”

Shoppers yesterday described how the 41-year-old Old Etonian appeared baffled by his bike’s disappearance.

He spent 15 minutes pacing up and down Portobello Road asking passers-by if they had seen it. One witness said: “He chained his bike to one of the bollards.

“There had been a couple of kids hanging around. They noticed he had chained it to a short bollard and they just picked it up and ran off.

“To start with he was not sure whether he had just left it somewhere else, then after a few minutes he realised it had been stolen. He was embarrassed and a bit annoyed. Most people didn’t recognise him. Once they did, quite a crowd gathered. He was a bit cheesed off.

“One man asked if he could have his picture taken with him and he just said: ‘Not now’.”

Others felt Mr Cameron had been a little naive. James Theophile, 60, said: “To leave your bike like that round here is simply asking for trouble.”

A Conservative party spokesman said: “Obviously David is quite hacked off by the theft of his bike, especially having locked it up.

“Unfortunately, these kinds of incidents affect everybody and he is just going to take it on the chin and deal with it.”