Air Raid Siren

Summary

Air Raid Siren, 1938.

Reasons for Designation

The Air Raid Siren, Cecil Road, Hale is listed at Grade II for the following principal reasons:

Architectural interest:

* it is an extremely rare example of an in situ Second World War air raid siren;
* as a well-preserved example of a late-1930s pole-mounted air raid siren, retaining all electrical switchgear and General Post Office equipment;
* it demonstrates a technologically and innovative use of the telephone system, allowing a central warning to be issued remotely to dispersed sirens over a large geographical area.

Historic interest:

* as a representative example of civil defence provision in England during the Second World War and the Cold War;
* it embodies historic and technical values that illustrate the all-encompassing nature of total warfare and the experience of the civilian population under aerial attack during the Second World War, and of the fear of nuclear attack during the Cold War.

History

During May 1938, the government established an air-raid warning system across the United Kingdom that was intended to sound a warning of 'Imminent air attack', allowing the Air Raid Precaution (ARP) services to take up their posts and the public time to take shelter, before any bombing took place. It consisted of a two-minute 'Air Raid Warning Red' that was sounded on a siren, using an alternatively rising and falling in pitch. Once the danger of attack had passed the All-clear or 'Raid Message White' was sounded in the same way but using a continuous constant pitch sound. These warnings could be sounded using portable hand-cranked sirens, or by large electrically operated sirens, mounted on public buildings such as Police Stations, Police Boxes, Town Halls, Fire Stations and so on., or on tall poles erected near-by to improve audibility (as is the case with the example on the site of the former Cecil Road Fire Station). The exact system of warning changed over time, but it relied on a warning being issued by Fighter Command Headquarters at RAF Bentley Priory to all Police HQs along the predicted track of an enemy air raid, this warning was then issued to all divisional police stations, who in turn alerted all local sub-divisional stations equipped with an air raid siren to be prepared for a possible attack (Raid Message Purple). Once the likely intended target was identified, a 'Raid Message Red' was issued to the Police HQ in the immediate area, who gave the warning to the relevant divisional station that cascaded the warning to its sub-divisional stations to sound the warning.

Post-war the air raid siren continued in its intended role; however, the development of nuclear and later thermo-nuclear weapons resulted in the system being adapted to provide warning of nuclear attack, controlled by the United Kingdom Early Warning Organisation (UKEWO). The General Post Office (GPO) talking clock (officially called 'Handel') was adapted as a 'carrier control' network; by using the talking clock system, the turn of a key at the United Kingdom Regional Air Operations Centre would simultaneously alert 250 carrier control points in divisional and some sub-divisional police stations. The press of a button at any of these control points would activate 7,000 powered sirens and would cascade the warning to receiver points around the country. Subsequent to the end of the Cold War in 1991, the siren was decommissioned in 1993 and the Home Office issued instructions in 1999 for the recovery of the majority of air raid sirens for scrapping, with only a small number left in position or installed at new locations to give warning of flooding.

Details

Air Raid Siren, 1938.

MATERIALS: a tubular steel post supporting an electrically driven siren, with a brick-built equipment cabinet.

DESCRIPTION: the siren is situated within a small rectangular-plan enclosure, formed by a chain-link fence carried on concrete posts, situated adjacent to the site of a former fire station. It is mounted on a tubular steel post, approximately 10.7m high, and an electrical supply cable and a junction box is attached to the outside of the post. It has a central steel housing attached to a steel mounting base plate and it contains an electrical armature motor with a central shaft that has a steel fan at either end, enclosed by a circular case with multiple stator sound vents with flaps. The ends of the encased fan blades are attached to a rotating hooped rotor vent with multiple rectangular stator vents. A small rectangular brick-built General Post Office equipment cabinet with a concrete slab roof, and closed by a pair of timber doors, is situated at the base of the pole, housing a 3 phase (440 volts) Air Raid Siren Control Unit.

This list entry was subject to a Minor Amendment on 23 February 2022 to reformat the text to current standards

Sources

Books and journals
Anon, , The Air-Raid Warning System in Newnes Practical Mechanics, Vol. unknown, (November 1941), 36-38
Brown, M, A Child's War, Growing Up on the Home Front 1939-45, (2000), 11 and 12
Brown, M, Put That Light Out! Britain's Civil Defence Services at War 1939-1945, (1999), 86
Cocroft, W D, Thomas, RJC, Barnwell, PS, Cold War, Building for Nuclear Confrontation 1946-1989, (2003), 220

Other
Air Raid Precautions Memorandum No.8 - The Air Raid Warning System, May 1938

End of official list entry

All text content is available under the Open Government Licence v3.0 , except where otherwise stated. Any supplied maps are © Crown Copyright [and database rights] 2026 OS AC0000815036 and may not be reproduced without permission.

Print the official list entry