The Kray twins, Ronnie and Reggie, were notorious British gangsters who operated in London during the 1950s and 1960s. They led the Kray gang, which was involved in various criminal activities, including extortion, robbery, and violence. The twins were known for their flamboyant lifestyle and connections to the London underworld. The Krays gained significant media attention and became infamous for their ruthless behavior and public persona. They were eventually arrested and convicted of murder in 1969, leading to life imprisonment. Their story has been depicted in various films and books, highlighting their impact on British crime history.