Designed to serve most of the South West of England and South Wales, the West Regional Transmitting Station at Washford Cross, was the fourth built as part of the BBC's 'Regional Scheme' and was opened in May 1933.
The BBC's first Chief Engineer, Capt. P.P.Eckersley originally proposed the Regional Scheme around 1924, the intention being to replace the existing low-power transmitters serving major towns and cities with high-power stations that would cover whole regions of the British Isles. The limited number of wavelengths available made coverage of the entire country impossible with low-powered stations as synchronisation of transmitter wavelengths to the required degree of accuracy was not possible at the time.
The Scheme started with the opening, in 1929, of a twin transmitter station at Brookmans Park to serve London and the South East of England. This was followed by similar stations for the North Region in 1931, the Scottish Region in 1932 and the West Region in 1933.
The West Regional station housed two 50 kilowatt transmitters designed for the Regional Scheme by BBC engineers and manufactured by Marconi's Wireless Telegraph Co. at Chelmsford. They fed aerials attached to two 152m (500ft) high masts, one radiating the 'National Programme' and the other, the new 'West Regional Programme'. By the time the National transmitter became operational, the synchronisation of transmitter wavelengths to the accuracy required to avoid reception problems in regions of service area overlap, had become possible. The National transmitters of Washford and Brookmans Park became the first high-power transmitters to share a wavelength.
By 1937, with the National Programme being easily available from the Droitwich transmitter, this service was discontinued from Washford and a new 'Welsh Regional Programme' was begun. However, coverage of the West Regional Programme was not as good throughout the South West of England as had been hoped and new stations at Clevedon near Bristol and Start Point on the south coast took over the West Regional service in 1939.
At the outbreak of World War Two, Washford, along with other BBC transmitters broadcast only the 'Home Service', but later the 'Forces Programme' was broadcast at various times also. With a return to peacetime programming, Washford broadcast the Welsh Home Service from July 1945.
In 1949, the building was modified and extended to accommodate a new Standard Telephones and Cables CM10 transmitter. This unit consisted of two 100kW transmitters capable of being operated in parallel and replaced one of the original Marconi 'Regional' transmitters. One half of the CM10 took over broadcasting the Welsh Home Service in March 1950.
On 30th September 1967, the BBC launched its 'Popular Music Programme', Radio 1 and this was broadcast from the other half of the CM10 transmitter.
On the same day the Welsh Home Service was renamed Radio 4 Wales the name changing again to Radio Wales in November 1978.
Towards the end of the 1970's the whole station was re-engineered for unattended operation and virtually all the original equipment was scrapped.
Three new air-cooled Marconi transmitters were installed in the former Machine Room for Radio Wales on 882kHz (100kW), Radio 1 on 1089kHz (50kW) and Radio 3 on 1215kHz (50kW).
The front half of the building was no longer required by the BBC but was saved from demolition when the whole station was given Grade 2 listing by English Heritage in 1984. Various schemes were put forward for use of the redundant Transmitter Hall, Control Rooms and offices including plans for a swimming pool and, in August 1986, a Trust House Forte restaurant in the grounds. However, the building remained empty until, in August 1987, planning permission was granted for conversion to a tourist attraction containing animals, tropical plants, children's' playground and caf facilities. The Tropiquaria opened to the public in May 1989 with heating provided by waste air from the transmitter cooling system in the adjacent part of the building. The Radio Museum (Wireless in the West), designed to give visitors an idea of the building's history and purpose, opened in April 1993.
Early in 1993, the BBC gave up use of the 1215kHz frequency which was taken over by Virgin Radio in April. They replaced the Marconi transmitter with a more efficient Harris DX50 unit. The 1089kHz frequency was given up in July 1994 and taken over a few weeks later by Talkradio UK who also replaced their Marconi transmitter with a Harris DX50.
In March 1997, all the BBC's domestic transmitting stations were taken over by Castle Transmission International (later to become Crown Castle UK Ltd.).