The programme was initially presented by Davina McCall from its inception to its cancellation by Channel 4. Despite being offered the position of presenter following the programme's move to Channel 5, McCall chose not to return. Former winner Brian Dowling became the presenter, a position he held throughout the twelfth and thirteenth series. Emma Willis later replaced Dowling as the presenter of the series from the fourteenth series onwards. Marcus Bentley has been the narrator of the series since it premiered in 2000. "Big Brother" has had numerous spin-off series occur since its premiere, most notably "Celebrity Big Brother", which is a shorter version of the main series wherein the cast is composed solely of celebrities. Numerous other spin-off series that are not competition based have aired, with Dermot O'Leary, Russell Brand, George Lamb, Emma Willis and Rylan Clark-Neal all presenting spin-offs. Over the course of its run, there will have been a total of 45 series of "Big Brother" in the UK: nineteen regular series, twenty-two celebrity series and four other series.