The Water Rats were founded in 1889 by comedian Joe Elvin. The first King Rat, as the head of the charity is termed, was music hall singer Harry Freeman. Legendary comedian Dan Leno joined in 1890 and was an early King Rat in 1891, and again in 1892 and 1897. The post is usually for one year.
Membership is limited to 200 long serving members of the industry. Some are household names but many are not. The present King Rat is Kaplan Kaye (2007), the son of Past King Rat Davy Kaye. Current members include: Max Bygraves, Con and Dec Cluskey of The Bachelors, Bert Weedon, Engelbert Humperdinck, Norman Wisdom, Lionel Blair, Des O'Connor, Frank Bruno, Frank Carson, Barry Cryer, Paul Daniels, Brian May, Nicholas Parsons, Roy Hudd, John Bardon and Rick Wakeman. Members of the public can become a Friend of the Water Rats.
The charity raises money by organising shows, lunches, dinners and other events. The objects of the charity are “... to assist members of the theatrical profession, or their dependents, who, due to illness or old age are in need.” Additional funds raised go to a diverse range of charities and good causes including hospitals, health charities and benevolent funds.