The scripts would then be re-written to add in topical references over the next few days. The 'completed' episode would then be recorded on the night before transmission, with some of the cast recording voice-over additions the next day, a few hours before transmission.
The series was set in the newsroom of a news TV station, and hence had to be topical. The character plots for each episode were written in advance, and delivered to the cast on the Monday before recording.