Site Records


SiteName: Criggion Radio Station

Criggion
Montgomeryshire, Wales
SJ283144

Sub Brit site visit 6th May 2003

[Source: Andrew Emmerson]

WHAT: Despite its obscurity and remote location, the name Criggion has attracted some attention on account of its reputation as a potential nuclear target for the Soviets.

Others will recognise the name as the terminus of one of Britain's strangest railway lines. The radio station described below belonged originally to the Post Office and after privatisation, to British Telecom

WHERE: "Craggy Criggion" lies in Montgomeryshire, close to the English border, roughly at the centre of a triangle bounded by Welshpool, Oswestry and Shrewsbury. The location is extremely picturesque and rural, close to the banks of the River Severn (Hafren) on flat watermeadows immediately below a massive outcrop of granite, the 900ft (or so) high Breidden Hill.

ITS FUNCTION: Secrecy surrounded Criggion in the past although a number of publications suggested that its role was chiefly defence-related, providing worldwide radio coverage on the very low frequency (VLF = long wave) band to ships and submarines (the station had nothing to do with the BBC and was never used for broadcasting to the public).

The Shropshire Star article (cited in full below) sums up what might be considered common knowledge when it states: "Although the exact role of Criggion is wreathed in secrecy, it is believed it acts as a contact point for nuclear submarines across the world and was a 'Category A' target during the Cold War."

Photo:The VLF Transmitter Building
Photo by Nick Catford

The Trident Ploughshares website is more explicit and asserts the station commanded Trident submarines, saying: "The main sites for command and control of Trident submarines include Criggion, Rugby, Anthorn and Inskip. These sites normally consist of radio masts and little else. Command and control systems begin with the Ministry of Defence in Whitehall, London. Actual operational instructions are transmitted from RAF Northwood. However, Trident is also linked into the US command and control system and with various NATO systems."

However, Peter Hennessey's book The Secret State (revised edition, 2003) blows away any remaining doubt with the statement, "Among [the Russians'] military targets were the very low frequency signals installations at Rugby and Criggion, whose purpose was and is to relay the Prime Minister's instructions to the commanders of the deterrent-bearing submarines."

CRIGGIONS HISTORY: Criggion radio station was born as a direct result of Hitler's war and the Admiralty's realisation that Rugby's VLF transmitter (callsign GBR), vital to the war at sea, had no standby and might be severely damaged or destroyed by stray bombs intended for nearby Coventry. A crash programme was therefore set in motion in 1940 to remedy this situation and to provide additional high frequency (HF = medium wave) transmission capabilities across the Atlantic. The aerial for a VLF transmitter occupies a large area (because of the long wavelength) and needs very high masts to support it.

Since only three suitable 600 ft. high masts were available in the country at that time, it was decided to seek a site where they could be located on a large plain flanked by a hill to provide a fourth anchorage.


The original VLF transmitter masts

Not an easy task; but eventually Criggion, on the Welsh/English border, was discovered and all the paraphernalia of construction descended on that sleepy Welsh village.

Staff were hurriedly assembled, billets found in Oswestry and a large private house Ardmillan House) requisitioned as a hostel. The latter was the scene of much coming and going at the oddest of hours, and the profits of the local pubs benefited greatly


The VLF Transmitter Hall
In September 1942, the first HF transmitter was put into operation. Early in 1943 while Criggion's VLF transmitter was still in the testing stage, Rugby's GBR caught fire (not due to enemy action). Testing was accelerated and within three days Criggion's new transmitter had taken over the Admiralty service to HM ships at sea. A lucky break, for Rugby was out of action for six months. Criggion's GBZ played an important part in the sinking of the Scharnhorst and the capture of the Altmark, and letters of thanks were received from the Admiralty for the assistance given.

Additional HF transmitters were installed between 1943 and 1945; all of these had been taken out of service by 1970. The VLF transmitter and antenna were renewed in the late 1960s and the new equipment came into use in 1969. Further transmitter renewal came in 1983 and 1991.

From the outset the telegraphy signals transmitted by Criggion were sent over landline cables from the armed services' own control centres, with no intervention by Criggion's own staff. Had a cable breakdown occurred, a naval rating would have been sent to operate an emergency Morse key at Criggion but it is understood this never happened.

Further information and pictures about this site continues here

[Source: Andrew Emmerson]

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