The crew stayed in the apartment location for several days during filming. Unbenownst to the crew, a father had shot and murdered his young son and himself in the apartment a few months prior.
Addison LeMay flew to London to immerse himself in the Cockney culture prior to filming.
Daniel Keith had to lose 25 pounds to play the part of Rambler. During filming he was 150 pounds and only 5% body fat. He also shaved his head and worked for months with stunt and knife fighting coordinators.