|Broadcast area||East Surrey and North Sussex|
|Frequency||97.5 MHz, 102.7 MHz|
|First air date||20 October 1984|
|Audience share||7.4% (December 2009, )|
Mercury FM was a radio station in the Surrey and Sussex area of the United Kingdom that was founded on 20 October 1984 and closed on 25 July 2010. The station broadcast on FM 97.5 MHz in Horsham and 102.7 MHz in East Surrey and Crawley and later merged with Heart Sussex to form Heart Sussex and Surrey.
Radio Mercury began airing on 20 October 1984, on 103.6 FM and 1521 AM. A year later, the FM frequency changed to 97.5 in Horsham and 102.7 in East Surrey and Crawley. In 1991 the station merged with County Sound Radio in Guildford to form the Allied Radio Group. Mercury then went from playing a broad mix of music to being mainly a Top 40 station, County Sound was later renamed "Extra AM" and then again was shortly renamed to "Mercury Extra AM" to make the connection between the two stations better known. It also became known as The Breeze, until the Classic Gold Network took over the AM licence of 1521 kHz. Mercury was renamed "Mercury FM" after the takeover of the group by GWR, later GCap Media. Before that Mercury lost the County Sound region again, and Eagle Radio took the Surrey 96.4fm transmitter, and County Sound returned to 1476am. The station was incorporated into GCap's "One Network" of stations, until the merger between GCap and Chrysalis Radio, forming Global Radio. As part of this merger, many of the former One Network stations were rebranded and reformatted under the "Heart" network. However it was decided that given the proximity of Mercury's coverage area to the existing Heart 106.2 station, it would retain its identity and be formatted as a "Hit Music" station.
It was announced, that Mercury FM would become part of the Heart Network. The newly merged Heart Sussex and Surrey launched on Monday 26 July 2010 with the very last Mercury FM programme broadcast the day beforehand. Currently, sales operations continue to be run from Crawley.