CONRAD (Control by Radio) Post Nuclear Strike Government Communications

A declassified document 'UKCICC(H) - JSI' from the U.K. National Archives reveals a very secret communications system only to be deployed after a nuclear strike. Operated by the Royal Signals, it would have provided a limited capacity network for both Military and Civilian Government messages. This page summarises the important parts of the CONRAD system and its use for Civilian teleprinter messages.

Throughout this website, I have used the term Regional Government Headquarters (RGHQ) which was the name used for these centres at stand-down, they have been given various titles over their life, this Joint Signal Instruction (JSI) uses the term SRHQ (Sub-Regional Headquarters) which was the current name given to RGHQ's when the document was created.

The CONRAD Network

Simplified Annex F in the Joint Signal Instruction

CONRAD Gateway diagram

Following a nuclear strike on the United Kingdom, it is likely the damage would significantly disrupt landline communications. At the time the GPO had a monopoly of landline communication in the United Kingdom. Not only did it provide the public telephone and telegraph network (TELEX) but anyone with their own private switching units had to lease a landline (private wire) from the GPO, to connect those switches together. The UKWMO, RGHQ network (GCN), Military telephone and Military telegraph all had their own switching but relied on GPO landlines. The Country's eggs were all in one basket.

The UKWMO and GCN also had standby VHF and UHF radio circuits in case of landline failure due to an attack, but these routed via exposed hilltop sites which also may have sustained blast or EMP damage.

Key to Drawing:
AFHQ: Armed Forces HQ
SRMHQ: Sub-Region Military HQ
RGHQ: Regional Government HQ
ACHDF: Air Commander Home Defence Forces
UKLF: HQ U.K. Land Forces
CINCNAVHOME: Commander-in-Chief Naval Home Command

The declassified JSI on the subject of severe landline disruption
47. In this situation, Regional Military Commanders and Sub regional Military Commanders will use the facilities of the CONRAD radio teleprinter communications system, the Sub Region Military Command Net, and the Regional Command VHF radio system (project MOULD) when in service.

The declassified JSI gives a General Description,
56. The military Home Defence radio communication system is shown in outline at Annex F. It is referred to as the CONRAD (Control by Radio) communication system, and is essentially provided by the TAVR Signal Regiments of 2 Signal Group, with certain links / radio terminals provided by other units of all three services.

57. CONRAD communications are established in the POST STRIKE phase, for the purpose of providing an early National Communication System to be used by both civil and military authorities in the task of the recovery of the Nation.

58. Essentially, the system consists of a number of HF radio teleprinter links from three GATEWAY locations to surviving AFHQs and SRHQs / SRMHQs. Additionally, a further four radio stations are provided for each Sub Reg Mil Comd for the control of military units under his command.

Maintaining Secrecy During Exercises and Pre-Strike Phase

The JSI has this to say about exercises.
99. CONRAD radio stations are only to be exercised in peace using exercise locations, frequencies, call signs and drill traffic quite unconnected with the Home Defence Plan and this Joint Signal Instruction. ..... (not relevent)...

100. If the exercise envisages the testing or use of military circuits in SRHQs, application is to be made to the Secretary UKCICC(H), who will request authority from the Home Office and (if access is authorised) notify any special requirements concerning dress / use of military vehicles etc. .....

The JSI calls for silence so as not to identify targets for the strike.
65. From the time that deployment begins, radio silence is to be maintained by all HF radio links / nets, except for the command nets of the Sub Reg Mil Comds, who may activate such communications provided that no transmissions are made from Headquarters locations PRE STRIKE.

Each GATEWAY needed connections into the peacetime network to handle calls, if any part of it remained serviceable. These landlines needed to be set up well in advance of the war situation. If they were set up at the actual location it would disclose the position of the GATEWAY to be adopted in war. In order maintain secrecy, the landline circuit were terminated at pre-designated pick up points. Each pickup point had one telephone circuit to a Military Zone or Group Switching Centre and one telegraph circuit to a TASS terminal. Note: TASS is the acronym for the military Teleprinter Automatic Switching System, in use at that time and should not be confused with a similar acronym used by the British Post Office to delivery telegrams. Post Strike, these two circuits would be extended by radio links to the actual location of the GATEWAY unit.

Avoiding EMP Damage During the Nuclear Strike Phase

The Joint Signal Instruction, describes precautions to take when the strike is imminent to avoid Electro-Magnetic Pulse (EMP) damage to radio and terminal equipment. It is all pretty standard, so not included here. The interesting bit, when do you start using CONRAD ?

69, Comd 2 Sig Gp is to arrange the provision of peacetime telephone and telegraph circuits to "pick up points" as described at serials 8 and 9 of Annex B. . . . .

70. GATEWAY Comds are to maintain contact if possible during the STRIKE phase (using the line communications described at Para 69) with HQ UKLF, HQ 2 Sig Gp and the nearest AFHQ to their location. These HQs will advise GATEWAY Comds as to when the STRIKE phase is considered to be complete and when listening watch should begin at GATEWAY locations.

71. In the event of such contact with military HQs not being established or maintained, GATEWAY Comds are to observe the following instruction: When a period of 24 hours has elapsed since the last known nuclear explosion the GATEWAY Comd is to issue instructions at his site for a listening watch to be maintained at his location on all nets / links from 0800Z on the following day.

72. GATEWAY stations are not to transmit until, they have identified a call from their substations, as described at paras 74 - 76.

Message Security Levels

Perhaps surprisingly the secrecy measures for the CONRAD communications were quite relaxed. This must be seen in context of the GCN and UKWMO communications (dealt with elsewhere on this website) which was transmitted in the clear. The JSI states:-

Communications Security during the POST STRIKE Phase
106. During the POST STRIKE phase, when the role of the armed services is to assist the civil authorities in the recovery of the Nation, communication security is of reduced significance and is not to restrict the speedy transmission of messages.

107. However, during this Phase, there will be a significant quantity of sensitive messages which should be denied to the public. It is important therefore that such messages should be transmitted by a protected means if possible.

108. Existing military security classifications are not to be used during the POST STRIKE phase, being replaced by the sole classification of "SENSITIVE", which is to be used to identify messages which are to be transmitted over protected circuits where such circuits exist.

Staffing of the Node Points

CONRAD Troops

Staffing levels of CONRAD units

Click here for Staffing Breakdown List

As this website concentrates on communications, there has been no consideration of staffing levels in other topics. However to illustrate the huge scale of the CONRAD operation in support of Home Defence the JSI Appendix to Annex 'J' shows this amounted to 193 officers and 1,959 other ranks of Territorial Army Volunteers.

CONRAD Vehicles

CONRAD Convoy Paused

Convoy of CONRAD Vehicles

CONRAD Deployed

CONRAD vehicles with aerials deployed

The photographs show a convoy of CONRAD vehicles parked by the side of a road and two vehicles deployed at the AFHQ in Edinburgh.

CONRAD replacement HDRS (later known as NCRS)

In the early eighties a replacement for CONRAD was deemed necessary which in the contract planning and bidding phase this project was known as 'CONRAD 2'. The name of the project soon changed to Home Defence Radio System (HDRS) to identify it separately from the previous Conrad system. Like many MOD projects it went through its ups and downs with changes of requirements, cost and time scales over-runs until the project was put on hold. When the project was resurrected the name was again changed to National Communications Radio System (NCRS) and that is what went into service in the late eighties.

NCRS did not have Gateway Stations, it was an HF system that used ALE (Automatic link Establishment) to find a suitable working frequency. The equipment that was housed in the green 'horse-box' trailers was intended to be dismounted and re-assembled in its operating location. There were Master stations in the net but they did not act as gateways, and in effect any station could take over the master role which was there for net control and timing.

On his excellent website, www.radiomuseum.co.uk Allan G3PIY describes the HDRS equipment in a humorous style and provides many photographs of the equipment in the HDRS box trailers. He also provides documentation contradicting Paragraphs 99 and 100 in the Joint Signalling instructions. Clearly by the time of Exercise Brightfire in September / October 1989 thinking had changed so the RGHQ's were involved in the exercise.