Almost all episodes of the show featured live performances from a singer or band. This enabled the BBC to categorise the show as 'Light Entertainment' rather than 'Comedy', and therefore provide a bigger budget per episode, as budgets for Comedy were significantly lower.
The first series follows something of a 'fly on the wall' format, where various sketches are linked to the making of the show itself (for example, scenes featuring the wardrobe and make-up departments). This format was abandoned after one series in favour of a standard sketch show structure.