Big Brother 2003, also known as Big Brother 4, was the fourth series of the British reality television series Big Brother. It was based upon the Netherlands series of the same name, which gained notoriety in 1999 and 2000. The series premiered on Channel 4 on 23 May 2003 and lasted nine weeks, ending on 25 July 2003. The housemates were competing for a grand prize of £70,000, with Cameron being crowned the winner of the series on Day 64.