Cycling* England collects figures on participation in different sports. The latest statistics were published last week, and relate to the year up to October 2011.
Sport England measure the proportion of adults participating in different sports. The measure of cycling covers recreational and competitive cycling but not cycling for travel purposes. It includes BMX, cyclo-cross and mountain biking.
In the first part of their survey year I would have qualified as participating in cycling, in the second part of the year I wouldn't. However, more than 8% of survey respondents did. That's more cycling than kicking footballs, and more than twice as many cycling as hitting golf balls. There are a lot of swimmers.
However, the detailed report on cycling shows that the amount of organised cycling remains fairly static, but there is a decline in informal cycling, and among some age groups.
* Not Cycling England, of course - that should be Sport England