Sport England’s Active People Survey measures the number of people taking part in sport across the nation. It reaches 165,000 adults (age 14 and over) and began in 2005/6. Findings are published every six months.
Participants report their individual activities, such as swimming, cycling and running, so measuring triathlon data accurately is problematic. The number of individuals participating in triathlon is recognised to be well in excess of 100,000 on an annual basis.