Jack Regan is a slobbish, old style cop whose unsubtle methods usually get results, to the annoyance of internal affairs officer Lewis, who would be even more annoyed if he knew that Regan was having an affair with his young wife, policewoman Nancy. After Regan disobeys orders and a shoot-out in central London following a bank hold-up ends in carnage, he is stripped of office and briefly imprisoned. However, thanks to the loyalty of his young protege George Carter and a little string pulling from his superior Frank Haskins, Regan is released to bring down the villains in a gun battle at Gravesend marina, ensuring the continued existence of his department - the Sweeney.