They're the perfect getaway vehicle: conveniently placed on every street corner and free for the first half hour of any escape.
But the Mayor of London will be dismayed to discover his namesake Boris bikes have been used in number of muggings.
Data obtained by the BBC from the Metropolitan Police reveals that this summer at least three robberies have been carried out by thieves riding the distinctive blue bicycles. One July evening saw two separate thefts in central London. Both times an iPhone was taken from an otherwise unharmed victim.
A third incident occurred in May, when a gang of six men on Boris bikes surrounded the victim in Maida Vale. The gang stole his BlackBerry mobile phone, wallet and Oyster card.
Although handy, the bikes have drawbacks when it comes to illegal usage. Every rental is linked to a credit or debit card, with journey details stored by Transport for London. Equally, individual bicycles can be easily identified by a five-digit number on the frame.
Experts were dismissive of their suitability for a quick escape. "They're one of the heaviest bicycles you can imagine riding," Simon England, of The London Cycle Workshop, said.
"I suppose they might help you blend into the crowd quickly in central London – just at the speed of a pedestrian."
A spokesman for Transport for London said: "The vast majority of customers look after and use the bikes for their intended purpose."