A bookmaker (or bookie) is an organization or person that accepts and pays out bets on events at agreed odds, with the first known bookmaker, Harry Ogden, operating at Newmarket in 1795. In the UK, the Gaming Act 1845 restricted gambling to race tracks, leading to a thriving but often illegal betting culture with runners, clock bags, and bodyguards, though some operators like Bella Thomasson were overlooked by police. To guarantee profit, bookmakers act as market makers by adjusting odds to achieve a "balanced book" and may lay off risk with other bookmakers, similar to how actuaries balance financial outcomes. The industry was legalised in 1961 under Harold Macmillan, growing to over 15,000 shops before consolidating to around 6,219 by March 2022 due to Covid-19, with the "Big Three" being William Hill, Ladbrokes, and Coral. Modern regulation came via the Gambling Act 2005, enforced by the Gambling Commission, which requires online sites to be registered in the UK. Today, bookmakers accept bets on professional sports like horse racing and football, as well as political elections and novelty events, with online and high street gambling at an all-time high.