Known as Incremental radio stations, they had to offer output not already available on ILR, such as specialist music or unique programmes for a specific section of the community.
In May 1993, the Radio Authority prematurely terminated Sunset's licence, apparently accusing the station of providing inaccurate information about its financial and management affairs.
The liquidator was later to re-apply on behalf of Sunset Radio for its re-advertised licence - but lost out to Faze FM, who had proposed a dance music format.
Other than the weekday drivetime shows and local news, the majority of Capital's output is networked from London.
The output is similar with many of the original DJs including Mike Shaft, Steve Quirk and Audrey L. Hall.