According to this BBC report, bicycle crime in the capital has escalated significantly in recent years.
The Metropolitan Police said that over 26,000 bikes were reported stolen last year, a rise of a third in the last half decade. Less than four per cent (under 1,000) were tracked down by Scotland Yard, which encourages cyclists to security mark their bike.
Whether that huge rise is down to a rise in cyclists, more accurate reporting of cycle theft, or a genuine rise in theft is arguable. The LCC said that the figure might be the tip of the iceberg, and added that when a bike is stolen around two thirds of cyclists don't get back on a bike.
There are a number of cycle crime prevention initiatives available, including the recently launched BikeSecure. Lock firms like Kryptonite also run online registration schemes, and then there are some cunning bike tracker devices currently on the market - like this one from SpyBike. Earlier this year, Bike Dock did some depressing video research into bike theft here.
Register for the BikeBiz News Digest at the registration page.