Mike Bullen has sole writing credit on 26 episodes of the series; four episodes of Series 3 were written by David Nicholls, and Bullen co-wrote one episode of Series 4 and 5 with Mark Chappell and Matt Greenhalgh respectively. Bullen usually wrote ten pages of script per day, whatever the quality of his writing. His own third draft was usually submitted to the producers as the "first" draft. As he was still an inexperienced writer by the time production of the first series began in January 1998, Bullen was aided by Christine Langan, who pitched in as a script editor. Storylines were planned in advance—the producers knew that they wanted to split up Adam and Rachel at the end of Series 1—but the later scripts were written once filming on earlier episodes had already begun. The number of people on the development team varied; the third series' comprised Bullen, Langan, Harries, producer Spencer Campbell, script editor Camilla Campbell, ITV's controller of comedy, and a team of five writers.