Struggle for Survival

Governing Britain after the Bomb

Steve Fox


File 16  Civil Defence Communications and Warning back to contents
Wartime broadcasting - emergency communications - attack warning - Royal Observer Corps  
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British governments have recognised the importance of mass communication to both put over its own message and to boost morale since at least the time of the general Strike in 1926. During the last war efforts were made to ensure the “due functioning” of both the national press and the BBC and this continued throughout the Cold War. Although plans for censorship in wartime were abandoned in the late 1950s, to ensure it was giving the official message the media would have been managed at national level by a 2 tier structure originally established in the early 1960s if not before – 

1.       The Standing Committee on Information Policy with a Cabinet Minister as chairman. This would co-ordinate all official information and instructions to the public, maintain constant contacts with the media and generally oversee information policy. It would also direct -

2.       The Media Working Party chaired by the Prime Minister’s Press Secretary, which would co-ordinate, the issue of press notices and other official announcements.


The War Time Broadcasting Service 

The importance of broadcasting as a means of disseminating information and maintaining morale in an emergency had been recognised since the 1930s. During the Second World War the BBC had implemented detailed plans to ensure national broadcasting continued and these formed the basis of the post-war Wartime Broadcasting Service or WTBS.

The principal broadcasting centre for the WTBS  during the Cold War would would have been  “The Stronghold”. This protected studio and office suite was built alongside the BBC’s headquarters at Broadcasting House during the war and was later absorbed into an extension of it. The Stronghold allowed the government to make nation wide broadcasts until the nuclear attack or until the seat of government left London and also acted as the “primary injection point” for broadcasting attack warnings to the public. There was also a studio in the CGWR code named SCOUT that would allow Ministers access to broadcasting facilities.

During the Second World War, part of the BBC had been dispersed to a site a Wood Norton near Evesham and in the 1950s it was developed as the reserve headquarters for the WTBS. In the 1960s, a large bunker was built there to provide 4 radio studios and accommodation for 100 staff. However, its usefulness would have been limited by the difficulties in getting information to Wood Norton in the first place and then the relevance of national news to the survivors. A studio was also installed at the Corsham war headquarters in the late 1950s connected to Wood Norton

The initial ideas for a WTBS were sketchy but by the mid-1950s there were plans to provide a national radio service with two medium wave programmes. The BBC’s main high-powered transmitters could not be used because it was thought enemy aircraft would use them for navigation so 54 low-powered medium wave transmitters were installed around the country.  

The BBC revised its plans for the H-bomb era in 1957. The object of broadcasting in war would now be “to provide instruction, information and encouragement as far as practical by means of guidance, news and diversion to relieve stress and strain”. The last phrase appears to mean entertainment, which would have been provided by pre-recorded programmes and records. The idea was to provide a national radio service possibly broadcasting 24 hours a day although it was acknowledged that if the national electricity supply failed few people in the pre-battery radio era would have been able to hear it.

By the early 1960s, aircraft were no longer considered a major threat and the main transmitters, particularly those at Droitwich could now be used. At some time the main cable carrying the long wave (now Radio 4) service from London to Droitwich was diverted through the reserve site at Wood Norton giving it access to these transmitters. The plan from the late 1960s envisaged high powered medium wave transmitters being used at local transmitter sites which were provided with emergency generators and some fall-out protection. The decision to start the WTBS would be made at Cabinet level at a late stage in the pre-war crisis. At that point all broadcasting facilities, including BBC and ITV television would stop normal programmes and start broadcasting the frequencies for the WTBS. After an hour the WTBS would take over broadcasting one national programme originating from Wood Norton. This would carry government announcements and information interspersed with what was called “sustaining material”. Local transmitters would be used and after the attack these would allow for a regional system of broadcasts. Central government could then broadcast using this regional network. The Droitwich long wave transmitters would be held as a national reserve. Television would not be used as it was thought that it would divert people away from the vital national message to be carried by radio and would not be available after the attack.

The 1980s plans expected that the WTBS would not start until after a nuclear attack unless the broadcasting facilities nationally were severely damaged. It would provide a sound only service for a few minutes each hour restricted mainly by the need to preserve the batteries in people’s radios. There would be no entertainment content.

Alongside the national service, it was always planned to provide a regional one. Studio facilities were planned for the 1950s joint civil–military HQs. In the long term transmitters would be installed but until that time local transmitter sites would have been used and many BBC staff would have dispersed from London to these sites. The RSGs had small BBC studios for regional broadcasting linked to local transmitters as did the SRHQs and RGHQs that succeeded them. So from the 1960s the main user of the WTBS would be the Regional Commissioner who would try to reassure the survivors that some form of government was still in control and to issue advice and instructions about such matters as fall-out and emergency feeding. The local authority Controllers would be able to use the regional facilities to give out local messages. However, although broadcasting was seen as a vital service the money was not made available for these regional facilities and as late as 1970 it was reported that it would take several years to set up a completely effective regional network.

At various times during the Cold War thought was given the continued operation of the BBC’s External Services but the plans seem to have been very confused. During the 1950s suggestions were made that 5 country houses used for the purpose during the Second World War should be refurbished but these ideas were generally not pursued and by the end of the decade the idea of a post-war external service had been abandoned. There was however a suggestion in the late 1960s that the former site of the wartime Aspidistra secret transmitters should be used for the purpose. The idea does not appear to have been implemented but it is interesting as the site would later be used in the 1980s for the new Crowborough RGHQ.



Most communications pre-nuclear attack would be via the normal public telephone or telegraph circuits. Although the latter was largely replaced by fax by the 1980s, it formed the core of civil defence communications throughout the Cold War.  

At central government level the various ministries and departments had been linked since the 1950s by an extended Whitehall Teleprinter Network supplemented by a dedicated private telephone network switched through the private Federal exchange. In the early 1950s when plans were made for “due functioning” during a lengthy war two schemes were implemented to increase both the capacity and survivability of the line circuits used for telephone and telegraph. The first involved six massive underground exchanges in London, Birmingham, Manchester, Liverpool, Glasgow and Leeds although as mentioned in File 3 only the first 3 were actually built as mentioned earlier. These were supported by new strategic cable runs which included a series of massive blockhouses built to protect the repeater equipment.

The second system was publicly revealed in the 1955 Defence White Paper which announced “The Post Office…are planning to build up a special network, both by cable and radio designed to maintain long distance communication in the event of an attack”. This network, generally known as Backbone provided some additional trunk cable routes and protected switching centres but the most visible part of the system was to be a chain of microwave relay towers. The original scheme provided for 11 towers literally forming a backbone running from the south of England where the key tower at Stokenchurch is now passed daily by thousands of motorists using the M40, up the centre of the country and into Scotland. In the 1960s additional links were added in southern England from Fairseat in Kent via Kelvedon Hatch and Stokenchurch to the Fiveways Tower which virtually sits on top of the Corsham war headquarters site. Ordinary cable circuits would be connected into the Backbone towers to allow additional capacity for use in wartime. Although planning started in 1954, the scheme ran into major delays involving money and equipment design, and more surprisingly given the strategic need for the system it was constantly held up by problems with planning permission. It did not become properly operational until the early 1960s by which time its original wartime role had been largely overtaken by the need to provide additional peacetime circuits for telephone and TV transmission and the original 11 tower scheme, together with the extensions had been absorbed into the nationwide network of towers seen throughout the country today. 

During the pre-war crisis period, the public would put an increasing strain on the public networks, which might prevent official users from making calls. To counter this the Telephone Preference Scheme would be used. This was first introduced in 1962 although a similar system had existed for some years before. It divided all public lines into one of 3 categories. By making some simple adjustments at the exchanges, some 90% of ordinary subscribers could be prevented from making outgoing calls. This would leave the network free for the top two categories. The second category, with some 8% of lines, included schools, newspapers, foreign embassies, etc considered necessary to maintain the life of the community during a peacetime emergency. If necessary these lines could also be cut off leaving active only some 2% at places such as transport authorities and warning broadcast points considered vital to the prosecution of the war and national survival. Cutting off the public phone network would have been a blow to public morale and it was noticeably not introduced during the 1980s exercises.


The Emergency Communications Network

Without reliable and effective communications the civil defence control chain could neither receive information nor give instructions. The staff in the controls would be deaf, dumb and blind. The planners recognised this throughout the Cold War, and the vital communications systems were generally available for the higher levels of the control chain although they were totally dependent on the physical existence of the control buildings. If these did not exist, as was often the case, the communications systems were not installed.

A nuclear attack would destroy much of the infrastructure of the telephone and telegraph system and what survived would soon fail with the absence of mains electricity. A dedicated communications system was therefore established to link the civil defence controls. In the early 1970s, this Government Control Network was extended to link local authority controls to the regional ones. It was renamed the Emergency Communications Network (or ECN) in 1979 although it was strictly for wartime use. The aim of the ECN was explained in “The Emergency Planning Guidelines Handbook No 4 – Communications” published in 1989. It said “...the overall aim of the government’s civil defence communications programme is to provide emergency wartime communications to supplement surviving elements of peacetime systems for the control and co-ordination of action in war, particularly after a nuclear strike; and to support the operation of Regional Government in war including the wartime responsibilities of local authorities for survival operations...”

The ECN was based on “private wires” which are dedicated telephone lines independent of the public network connecting the main parts of the regional government system. As can be seen from the diagram below the RGHQs (and before them the SRHQs) were the hubs of the system. They were connected to neighbouring RGHQs, the main and standby County Emergency Centres and a few other key places in their sub-region. The County centres were in turn linked to the districts and some other places vital to them.


In the 1970s, the telephone systems in the ECN were based on small manual plug-board exchanges and the equipment took up a considerable amount of space. The equipment was usually old and in the local authority centres normally obsolete and inadequate. In the late 1980s, the manual switchboards were replaced by modern equipment. The RGHQs were each given two SX2000 units (plus one for testing) and the county controls one.

Although in later years the RGHQs and most county centres had extensive internal telephone extensions, much use was used in the earlier days particularly at local authority centres of “phonograms”. These consisted of an extension from the main switchboard in the control to a phonogram booth where an operator would write down each incoming message and then physically pass it to the recipient. Outgoing messages were handled in a similar fashion. The Kelvedon Hatch SRHQ for example had 3 phonogram booths prior to its 1976 refit.

The most common civil defence line based system was however not telephone but telegraph using teleprinters. These teleprinters allowed a message to be printed out at the receiving control. The system used was however a point-to-point one relying on a few central hubs. If one county control sent a message to a neighbouring one it would first go to the regional headquarters where it would be received as a punched (or “chadded”) paper tape. This tape would then be fed into the transmitting teleprinter at the headquarters connected to the receiving control. Alternatively, if the message were to be passed through several intermediate points it would pass through the Tape Relay Centre at the headquarters. The telegraph system used electro-mechanical equipment that had been designed in the 1930s. Kelvedon Hatch for example had 9 Model 7B machines although many controls used the later Model 15s. It was robust but demanding in manpower. More importantly, it was very slow and consequently the length of messages had to be restricted and there was obviously no way of holding a discussion via telegraph.



  Typical 1950s vintage teleprinter with paper tape reader




Tape Relay Centre at Brackla (photo by Ben Soffa)


Message Switching 

The deficiencies in the telegraph systems lead to the introduction in the 1980s of modern message switching equipment known as MSX. This was initially installed at Royal Observer Corps Group Controls and then at the RGHQs. By the mid-1980s, most county emergency centres had it although as late as 1990 some district emergency centres were still using the old equipment. MSX allowed much more flexibility in sending text messages, for example, the messages could be automatically switched between any site on the network doing away with the old Tape Relay Centres. Transmission was also faster and messages could be longer.


Emergency Manual Switching System

Some places that the regional level controls might wish to contact such as ports and power stations were not on the ECN or before it the GCN and the public telephone system would have to be used to contact them. After an attack it was assumed that even the restricted service available from the Telephone Preference Scheme would fail and reliance would be put on a last ditch rump of the service called the Emergency Manual Switching System or EMSS. This consisted of a few trunk lines some of which were permanently connected while others would be connected in the crisis period. They terminated at small manual switchboards known as Terminal Group Centres housed in ad hoc protected accommodation in the basements of some 250 of the larger telephone exchanges.  The centres were connected to one of 31 Emergency Zone Centres and through them to 6 Emergency Trunk Switching Centres. This would give access to a very restricted service at regional and possibly national level. RGHQs had two permanent EMSS lines as well as around 15 lines connected to the public system to back up the dedicated circuits in the ECN.



Radio was seen as a back up to line based systems. It was frequently referred to for use by all levels of the control chain from the 1950s and it would have been vital in establishing communications where the regional or sub regional control was established in ad hoc premises. In the 1960s, a lot of thought was given to the provision of radio to link the various controls and some sets were stockpiled but in many cases the radio equipment or the controls to install it in did not actually exist. It was however usually installed in the permanent regional level headquarters to be used if the line circuits failed. Most of the line circuits were effectively duplicated in this way and the equipment at the RGHQ or County centre could automatically send the message by radio if the line was not available. The radio transmitters used the “hill top” radio stations operated by the Home Office that were normally used by the emergency services.

The army had its own dedicated teleprinter circuits known as TASS (teleprinter automatic switching system) with a terminal at each regional headquarters. It would also make extensive use of radio. As well as the CONRAD system home defence units were equipped with a basic short-range radio system from the mid-1970s known as Mould.


Message procedures

The communications areas in the RGHQs and their predecessors followed a common design that dates back to earlier Civil Defence Corps and military practice. Messages, which had to be kept short because of the limited capacity of the systems, were passed to a Counter Room (sometimes called the Registry) in the Communications Centre or “comcen”. Here they were prepared for dispatch before being passed to a teleprinter (or later a VDU operator) to input the message. Incoming messages were handled in a similar way prior to being passed to the addressee. Messages on the ECN could be classified in order of priority as flash, immediate, priority or routine. There were no facilities to encrypt messages over the civilian circuits. In the late 1980s, the Home Office published a guide for users of the ECN and another on message handling and writing to help the communications teams in the RGHQs and local authority emergency centres most of who would have received little prior training.

Message handling at the emergency centres was supposed to follow the same lines as for the RGHQs but their comcens were both smaller and simpler. The diagram below shows a specimen district comcen as suggested in the ”EPG Handbook 4 Communications”.  



The Attack Warning System

When civil defence was re-introduced, the attack warning system based on sirens that had worked well during World War Two was refurbished but it was essentially one designed to cope with slow moving aircraft and give local warnings. It could not really deal with jet aircraft and then ballistic missiles so the system needed to be modernised. By the early 1960s, the Fylingdales missile warning radar was operational and could give a seven-minute warning of a missile attack. The decision would then have to be made to set off the attack warning sirens for the whole country. This initially caused a debate between the RAF in charge of the radars and the Home Office, which was in charge of the warning system as to who would take the final decision. This was not for any practical reasons but because they were both concerned more about the repercussions of sounding a false alarm.

A film from the 1950s shows a man at the BBC receiving the warning by telephone and then opening a locked cupboard and removing a gramophone record that he placed on a turntable. This presumably had a pre-recorded attack warning on it to be broadcast nationally but it was obviously not intended for the missile age. By the 1980s, the decision to trigger the warning system would have been made by a Home Office Warning Officer based at the “principal warning injection point” at the RAF’s Primary War Headquarters near High Wycombe or, alternately, from the back up at the United Kingdom Warning and Monitoring Organisation’s war headquarters housed in a large bunker near Preston. They were both linked to Broadcasting House and the reserve broadcasting facility at Wood Norton, but the attack warning could only be injected into TV and radio broadcasts from Broadcasting House.

The Home Office staff, as well as alerting the BBC would trigger the national siren system by alerting 255 Carrier Control Points located at main police stations around the country. On receiving the “national attack warning red” the control point operator would activate the large electro-mechanical sirens in his area. They would then alert volunteers at local Warning Points via small “carrier warning receivers”. These volunteers, mostly in rural areas would then sound hand-operated sirens. When the system was stood down there were 9760 hand operated sirens mostly dating from the 1950s and about 7000 power sirens in use. In addition, warning messages would be broadcast by the BBC over all available radio and TV channels. It was hoped that the message could be passed through the system to give the general population the famous “4 minute warning” of nuclear attack.

The power sirens were usually mounted on public buildings where they were vulnerable to attack from the weather and birds. Maintenance of the sirens was the responsibility of the local police and as one report by the Home Office’s Emergency Planning Research Group diplomatically put it “…there was strong evidence that this task had been carried out more conscientiously in some areas than in others”. Also, over the years, the level of background noise has increased in towns, as has the tendency to sound proof house. Tests in the late 1980s showed that the manufacturer’s claims for audibility had been greatly exaggerated and the system was only between 3% and 10% effective. And this assumed the sirens worked. Regular testing had been stopped in the 1960s and a test of 5 sirens in 1985 found that only one worked properly and 2 did not work at all. A review of UKWMO recommended in 1989 that the siren system should be replaced. But before any action could be taken, the system was effectively put out of action when BT withdrew the “speaking clock” telephone service that had been used to carry the activating signal to the carrier control points. Alternatives were considered but the end of the cold war overtook them and apart from a few kept to warn of coastal flooding the siren system was dismantled by 1993.

The warning signal would be the same rising and falling note from the last war. Information films advised people to go indoors or lie down in a ditch or depression. If driving a vehicle they should “park off the road if possible; otherwise alongside the kerb, but not near crossroads, or in a narrow street where it could obstruct fire engines or civil defence vehicles”.

The system could also announce an all clear meaning that there was no further danger of attack or as the Protect and Survive films reassuringly put it, “when the immediate danger of air attack or fall out has passed the siren will sound a steady note.” On hearing this, survivors could “…leave your cover…” In an area directly affected by a hydrogen bomb this would, of course, be of academic interest only. After attack, the arrival of fall out in an area could be announced locally by firing maroons from some 12000 “maroon points”, 9000 of which were collocated with hand siren sites. The spread of fall out would be monitored mainly by the monitoring posts manned by the Royal Observer Corps and plotted by their Group Controls from where the information would be fed to carrier control points, local authority controls and the RGHQs via the ECN – assuming it survived. Additionally, local authorities would establish local monitoring nets to give a more detailed view of local conditions.

The attack warning system was not designed to give local warnings of conventional air attack and could only really cope with one national warning of a missile attack, warning people to take cover. There were no public air raid shelters[1] throughout the Cold War but many injuries and deaths would have been prevented by warning people simply to take what cover they could thereby avoiding the dangers from heat flash and flying glass. The actual effectiveness of the system was however unknown and this illustrates many of the problems inherent in civil defence throughout the Cold War in that the system was not properly maintained and its effectiveness not seriously challenged or tested. It existed and that apparently was all that mattered.


The Royal Observer Corps

The Royal Observer Corps was the field force of the United Kingdom Warning and Monitoring Organisation, which was usually known as UKWMO. UKWMO was responsible for – 

  1. Originating warnings of the threat of air attack.
  1. Providing confirmation of nuclear attack.
  1. Provision of a meteorological service for fallout prediction.
  1. Originating warnings of the approach of fallout.
  1. Providing regional government HQs, local authority emergency centres, armed forces HQs, and nuclear reporting cells of the armed services in the UK, neighbouring countries and offshore islands with details of nuclear bursts and with a scientific appreciation of the path and intensity of fallout.

The Royal Observer Corps had given up its original role of spotting enemy aircraft by the mid-1950s and had taken on the task of monitoring the nuclear bursts and then the spread of fall out.. By the late 1950s, they were equipped with some 1550 underground 3-man monitoring posts designed to withstand a blast pressure of 10 psi. The effectiveness of these posts was however questionable as most were dependent on overhead telephone lines and it was estimated in 1967 that 42% of them would lose their line in the “standard attack”. About half the posts were closed in 1968 following “care and maintenance” and the remaining 873 were closed in 1992 when the Corps was unceremoniously stood down. The posts would have been able to plot the direction of a burst, its approximate size and then the passage of fall-out.  The post would then report this information at regular intervals to one of 24 Group Controls spread throughout the UK. These were further organised into sectors with “blisters” for the Sector Controls attached to the Group Controls at Horsham (Metropolitan Sector), Fiskerton (Midlands), Bath (Southern), Preston (Western and national war headquarters for UKWMO) and Dundee (Caledonian). Throughout its life, the Corp’s volunteers were keen and well trained and, like the other volunteer organisations would no doubt have done their duty on the day. They were however always under strength.



Royal Observer Corps monitoring post

[1] One odd exception to this rule was the provision of floodgates for the London underground. During the last war, 21 floodgates had been installed to isolate parts of the tunnel network to prevent flooding if nearby rivers or sewers were breached. From 1953-1958, a second ring of 18 gates was built in case an A-bomb breached the Thames. When the Victoria line was planned it was again decided that the tubes would be used as shelters albeit unofficially and the floodgate system was expanded during 1965-1968 to cover the line north of the Thames at a time when most other civil defence projects were being delayed by lack of money. The later section of the Victoria line south of the Thames was not however given floodgate protection. Although use of the tube system and the former Deep Shelters built in London during the last war as air raid shelters was sanctioned in 1952 the idea drifted and a working party finally concluded in 1967 that it would be impractical to equip them to the required standard and their proposed use was abandoned.

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