I have to admit I have my doubts to this being the truth, the whole truth and nothing but the truth. I have looked for some official numbers and could find none to support that London had surpassed Copenhagen and some of the other better know cycling cities. Unless ther have been some drastic changes most commuting is done by Train, Tube and Bus.

"Cycling in London has enjoyed a renaissance, particularly since the turn of the millennium. Cyclists find that they enjoy a much cheaper, and often quicker, way around town than those travelling by public transport or car.
Over one million Londoners own bicycles but as of 2008[update] only around 2 per cent of all journeys in London are made by bike: this compares poorly to other major European cities such as Berlin (5 per cent), Munich (12 per cent), and Amsterdam (28 per cent)[17] and Copenhagen (36 per cent).[18] Nevertheless this is an 83 per cent increase compared to that in 2000.[19] There are currently an estimated 480,000 cycle journeys each day in the capital."