Association football is the most popular sport in England, where the first modern set of rules for the code were established in 1863, which were a major influence on the development of the modern Laws of the Game. With over 40,000 association football clubs, England has more clubs involved in the code than any other country as well as the world's first club (Sheffield F.C.), the world's oldest professional association football club (Notts County), the oldest national governing body (the Football Association), the joint-first national team, the oldest national knockout competition (the FA Cup) and the oldest national league (the English Football League). Today England's top domestic league, the Premier League, is one of the most popular and richest sports leagues in the world, with six of the ten richest football clubs in the world as of 2019.
The club was founded in 1893 and joined the Football League in 1920. They were voted out of the league in favour of Ipswich Town at the end of the 1937–38 season, but returned to it 12 years later after it was expanded from 88 to 92 clubs. Twice in the late 1980s they came close to winning promotion to the second tier of English football, but a decline then set in and in 1993 they narrowly avoided relegation to the Football Conference. Between 2000 and 2005, Gillingham were in the second tier of the English league for the only time in their history, achieving a club record highest league finish of eleventh place in 2002–03.
The official name is periodically changed to match changes in sponsors and is now the Johnstone's Paint Trophy (for three years from 2006), the common nickname amongst the fans for the cup during this period is the "Paint Pot Trophy" or "Paint Pot Cup".