Your Archives beta version

We would like your ideas for improving Your Archives. Please leave your suggestions and comments on the Next steps page

Backbone radio link and radio standby to line links for safeguarding vital communications

From Your Archives

Jump to: navigation, search

This is a transcript of a GPO paper, dated July 1956, from CAB 134/1207. The last page of the paper contains a map. There is an image of this map below the transcript.

This transcript preserves the layout of the typewritten original, except for pagination and the underlining of some headings.



I.   Introduction

1.   This paper describes certain projects undertaken by the Post Office
for defence purposes.  It may be convenient for the Official Committee on
Civil Defence to have this report before it for the purpose of their review,
in the light of current policies, of defence expenditure by civilian

2.   The paper concerns the plan for a backbone radio link running north
and south through the middle of the country, avoiding large towns and
designed to provide as safe a route as possible for communications vital to
the prosecution of a war, and also a new scheme proposed by the Service
Departments for radio standby to line links to supplement the backbone
radio plan and the existing cable network. The backbone radio link has
been approved in principle by the Home Defence Committee and the Official
Committee on Civil Defence (HDC(54) 5th Meeting, and CD(O)(55) 2nd Meeting).
The present position is that considerable progress has been made with the
planning of this scheme, including the design of the radio stations and the
selection of suitable sites for them. The Post Office and the Ministry
of Works have discussed the plan with a number of organisations which are
interested, including the Council for the Preservation of Rural England,
and have also begun negotiations with the owners of land likely to be
required for the radio stations.

5.   In view of the pressing need to restrict claims on national resources,
it seemed desirable to review the plan as a whole in the light of present
economic circumstances, and the Chairman of the Official Committee on Civil
Defence accordingly arranged a meeting with representatives of the Admiralty,
the War Office, the General Headquarters of the United Kingdom Land Forces,
the Air Ministry, the Home Office and the Post Office. This meeting also
considered the proposal to supplement the backbone radio plan and the
existing cable network by radio standby to line links. The paragraphs
which follow summarise the discussion and the conclusions reached.

II.  The need for secure communications and the plans to provide them.

4.   Landline or equivalent communications are vital to (a)  the prime air
defence of the U.K., including early warning of attack, (b) the nuclear
bombing retaliatory effort, (c) control of naval operations, (d) control of
civil and military Home Defence forces, and (e) the linking up to Central
Government and Fighting Services Headquarters of long distance communications
to overseas.

     (a)  Our fighter defence is completely dependent upon the Post Office
     landline network for warning, control and the fighter defence and
     co-ordination of all efforts, including reinforcement of hard pressed
     areas, as is also the obtaining of the early warning of attack necessary
     to initiate the retaliatory effort.  The advent of the guided weapon
     either air-to-air or ground-to-air will not materially change this
     dependancy.  It will still be necessary for G.C.I. stations   to obtain
     warning of raids from their own radar or from early warning stations
     and then to co-ordinate the defence, allotting targets as may be
     necessary to chosen guided weapons units or to fighter aircraft. Due
     to the much shorter range of guided weapons and hence to a much tighter
     time factor, the need for passing target infomation and selection
     over long distances may even be more essential than with defence
     by aircraft.  The speed of modern raiding aircraft makes it essential
     to maintain communications for liaison and co-ordination between
     controlling stations such as G.C.Is. which are widely separated and
     between these control stations and A.D.O.C. for the general strategical
     control of the battle.  Secure landlines or the equivalent, connecting
     widely separated areas, are therefore essential to the air defence
     of the U.K.

     (b)  Communications for the conduct of the Bomber Offensive must be
     considered in two phases, the first covering the planning of the
     initial lift will have taken place in advance, using existing
     communications facilities undamaged by enemy attack;  the second,
     comprising the planning and despatch of the second and subsequent
     lifts, will depend to a vital degree upon the existence of secure lines
     or equivalent communications.

     (c)  The control of Naval operations, which includes the control of
     merchant shipping proceeding to and from the U.K. and allied ports in
     Northern Europe, has to be conducted from the various protected Area  and
     Maritime Headquarters, e.g., Northwood, Fort Southwick in Portsmouth,
     Chatham, Plymouth and Pitreavie and from subordinate Headquarters
     allocated to deal with maritime warfare in local Command areas around the
     U.K. and Northern Ireland.  These Headquarters must be linked together.
     Communications with ships must be maintained and as this can only be
     provided by long distance radio, it is vital that the Headquarters
     concerned should have safe links with the radio transmitting and receiv-
     ing stations involved.

     (d)  To co-ordinate Home Defence measures in the battle for survival
     after attack there will be a vital need for secure communications between
     the Seat of Government (and its standby) and the Regional Joint Civil/
     Military War Headquarters.  Secure communications will also be needed
     between the various operational headquarters of the Fighting Services
     and between other Government establishments.

     (e)  The Government in the United Kingdom must be kept in touch with
     the Governments of the Commonwealth and other countries.  Departments
     and Defence Services at home will also need overseas communications.
     These depend on links within the United Kingdom to the radio and cable

5.   These requirements for secure communications cannot be met by the present
cable system of this country.  The main long distance cable network used at
the present time to provide trunk and private wire services terminates in, or
passes through, the largest cities in the country, and depends for its
operation on equipment located in these cities.  A heavy attack by nuclear
weapons would completely disrupt this network, and physical protection of the
plant, e.g. by placing it in underground accommodation, would be ineffective
against ground—burst megaton type weapons.   Post Office plans for protecting
vital trunk and private wire coumunications are based, in the first place,
on using a number of secondary cables which would be reasonably secure
against nuclear attack on the most likely target areas.  This "skeleton
cable network" would be supplemented by the "backbone radio link" and the
"radio standby to line links". Comments follow on the plans for developing
these three elements.

     (a)  The Skeleton Cable Network.  The network will consist of a
multiplicity of cables up and down the country which do not pass through
the largest towns.  Many of these cables exist but they will be supplemented
by new cables which will be laid to bridge present gaps.  The Post Office
is pursuing a steady programme of work on this scheme but it will be several
years before the network can be completed.  Even then its capacity will be
insufficient to provide more thana fraction of the lines required in a
network of long distance circuits giving national coverage for essential
traffic as well as safe routings for all vital private wires.  It is for
this reason that it is proposed to supplement it by the backbone radio
link.  The expenditure estimated to be required for completion of the
skeleton cable network can be put broadly at £3m.

     (b)  The Backbone Radio Link.  Under this plan 14 radio stations will
be established;  their proposed location is shown in Appendix 1 and the
route to be followed is shown by dotted lines in the map attached.  All the
stations are sited more than 10 miles from likely target areas, but most of
them are within 20 miles of such areas.  The link will provide four working
broadband channels and two standbys. Each working channel will have capacity
for up to 600 circuits and two will be available for defence circuits, the
other two being used to meet peacetime telephone trunk and television
development.  Spur connections from the main link to the Grantham area and
to the Shrewsbury area are planned.  The backbone radio link and its
spurs will not only supplement the capacity of the skeleton cable network
but will provide an alternative channel of communications over a different

     The radio station buildings will consist of a tower for the radio aerials,
surrounded at its base by a protected structure to house the apparatus and
provide accommodation for staff who, in times of emergency, will need to live
at the station.  The base structure will be windowless, and protection
against blast and fall-out will be on a scale agreed between the Post Office,
the Home Office and the Ministry of Works.

     The total cost of the backbone radio link is estimated at £9.2m.
(including £4m. for the buildings, the aerial towers and the access roads,
and £O.7m. for the television, etc. channels).  The spur links to Grantham
and Shrewsbury will cost a further £1.3m. The target date which the Post
Office had hoped to achieve is 1961.

     (c)  Radio Standhy to Line Links.   Even when the backbone radio link is
available, many of the Defence Services private wires, especially the shorter
ones, will still be carried entirely by cable, and those which are routed via
the backbone radio link will be connected to it by cable from the Headquarters
or other establishments of the Defence Services.  The purpose of the radio
standby to line links is to provide alternative channels of comuunication to
those provided by cable.  The main reasons why these are considered essential
are as follows:-

     (i)  The Fighting Services, in particular the Royal Air Force, have
     certain operational communications of such vital importance to the defence
     of the country that every possible precaution must be taken to ensure
     they are not interrupted.

    (ii)  Although the cables carrying the shorter distance private wires or
     connecting Services establishments to the backbone radio link do not
     normally pass through large towns (or if they do the vital private wires
     will be diverted to the skeleton cable network), the cables themselves
     depend on large numbers of repeater stations above ground and there is
     the clear risk of interruption by damage to these stations.

   (iii)  For circuits of the highest importance the Fighting Services
     consider that there must be alternative channels and that these can best
     be provided by radio relay links.  Even these links would not be
     completely safe since the radio stations themselves might be damaged, but
     the availability of both cable and radio systems differently routed would
     greatly reduce the risk of complete loss of vital communication facilities.

    (iv)  It would be easier to give effective protection against sabotage
     against the relatively small number of radio relay stations required for
     the standby to line scheme than to the much larger number of repeater
     stations serving the cable network.

After detailed discussion between the Post Office and the Fighting Services
a selective scheme for additional relay links has been drawn up, these being
listed in Appendix 2 and shown by full lines on the attached map.  The radio
relay system would by no means cover the whole operational area of the country,
but only those areas where private wires in cables serving essential
establishments pass through areas where the risk of damage to the cables, or
their repeater stations, from attacks on nearby urban centres or airfields
cannot be regarded as negligible.  Each of the links would carry between 25
and 150 private wires.  A radio relay system covering the whole country is
estimated to cost about £18½m., and the scheme now agreed between the Post
Office and the Service Departments is estimated to cost about £9m., including
the cost of special buildings designed to give protection against blast and

     The scheme is an integrated one designed to meet, wherever possible, the
needs of all the services.  Moreover, by making this scheme in effect part of
the Post Office vital communications network, the greatest degree of flexibility
in arranging alternative routings can be secured;  it is therefore proposed
that this network should be provided as far as possible by the Post Office, but
in individual cases where the Services consider that a complete radio standby
is essential to provide a few circuits for a particular establishment this work
will be undertaken by the Services themselves.

III. Summary of agreement reached at the inter- Departmental Meeting on 8th May,

6.   The agreement covered the following points:-

     (a)  The skeleton cable scheme, the backbone radio link and the radio
     standby to line links will constitute a highly important part of the
     preparations for the defence of this country in global war.  These schemes
     are essential to the maintenance of communications required by the civil
     and military Home Defence authorities.  Besides being a measure to
     strengthen national communications generally, the backbone radio link will
     meet the essential need for an alternative line of communications running
     from north to south of the country to carry circuits between the planned
     Seat of Government (and its standby), the various operational Headquarters
     of the Defence Services, the Regional Headquarters and other Government

     (b)  From the point of view of the Fighting Services, the radio standby to
     line scheme has equal importance with the backbone radio link itself;
     indeed, without it the Services could not regard the communications plan
     as meeting their essential requirements.

     (c)  If the backbone radio link and the radio standby to line links were
     not provided, the Fighting Services would be obliged to make other arrange-
     ments to meet their requirements, and these might well prove almost as
     expensive as the present plan.  The integration in single systems,
     whether cable or radio, of Services and civilian needs, has clear

     (d)  Together, the skeleton cable scheme, the backbone radio link, and
     the radio standby to line links, would provide alternative remote control
     circuits needed by the Seat of Government, Command and Regional
     Headquarters for the various wireless transmitting stations required for
     overseas communications and defence purposes.

     (e)  The backbone radio scheme should include protection against fall-out
     on the same scale as is being adopted for key installations generally,
     e.g. for the headquarters of regional commissioners.  The saving that
     could be obtained by omitting such protection would amount to £½m. out of
     a total expenditure of over £9m., and it would be false economy not to
     provide it.

     (f)  While the number of channels planned for the backbone radio link
     might appear high the saving which might be obtained by reducing that
     number would amount to about £¼m. only and such economy would not be

     (g)  The rate at which the schemes could proceed must depend primarily
     on the rate at which money could be made available, having regard to
     the competing claims on national resources and on the limited funds
     available for defence schemes undertaken by civilian Departments.

     (h)  Certain parts of the backbone scheme, and the standby to line scheme,
     are more urgent than others, and priority should be given to the southern
     backbone link and the southern spurs.

IV.  Cost.

7.   The total cost of the backbone radio link and the radio standby to line
links and the phasing proposed, may be summarised as follows:-

                                                    Estimated    Chargeable
                                                   total cost    to civilian
First phase   - Southern half of backbone link,
                i.e. to Skipton.                     £4.9m.        £1.7m.
                Spurs to Grantham and Shrewsbury.    £1.3m.

Second phase  - Standby to line links associated
                with southern half of backbone
                radio link.                          £7.6m.

Third phase   - Northern half of backbone radio      £4.3m.        £1.3m.

Fourth phase  - Standby to line links associated
                with northern half of backbone       £1.2m.
                radio link.

8.   The finance required for these schemes will need consideration, not only
in the light of the funds that will be made available for defence expenditure
by civilian departments, but also in relation to Post Office capital invest-
ment as a whole, this investment covering, as it does, not only expenditure
required for civilian development but also for defence purposes.  A firm
decision to go ahead with these defence projects will involve a financial
commitment in the years beyond those for which capital investment for Post
Office purposes as a whole has yet been approved.  Moreover, the provision
of alternatively routed private wires by means of the backbone radio link,
and the radio standby to line links, are expected to be more expensive than
the normal method of providing such circuits in cables, and it will be
necessary to consider whether a special method of charging for such circuits
should be adopted.

V.   Conclusions.

9.   The Committee is invited:-
     (1)  to take note of the agreement reached inter-Departmentally (paragraph
     6 above) on the importance and content of the backbone radio plan, the
     radio standby to line scheme, and the associated cable schemes;

     (2)  to consider, in the light of current general policy in regard to
     defence espenditure by civilian Departments, whether these plans should
     proceed on the basis described in paragraph 7.

General Post Office                                  July, 1956

TOP  SECRET                                        Appendix 1

                    Proposed Location of Radio Stations

                       in the Backbone Radio Scheme

          1.   Tring, Herts.
          2.   Charwelton, Northants.  
          3.   Coalville, Leicestershire.
          4.   Pye Green, Staffs.
          5.   Sutton Common, Staffs.
          6.   Saddleworth, Yorks.
          7.   Hunters Stones (Skipton), Yorks.
          8.   Azerley, Yorks.
          9.   Richmond, Yorks.
         10.   Muggleswick, Co. Durham.
         11.   Cold Fell, Cumberland.
         12.   Lockerbie, Dumfries.
         13.   Green Lowther, Dumfries.
         14.   Kirk O'Shotts, Lanarkshire.

TOP  SECRET                                           Appendix 2

                       Radio Standby to Line Links

Spur to:-                  Services and other communications to be provided

Ayr                        Gailes G.C.I. Station.

Boulmer                    G.C.I. Station, R.O.C. & Regional commmications.

Seaton Snook               G.C.I. Station.

Forest Moor                Admiralty Radio Receiving Station.

Shipton                    R.A.F. Sector Operations Centre.

Preston                    R.A.F. Sector Operations Centre and Regional
                           Commissioner's H.Q.  Admiralty Radio Transmitting

Grantham                   R.A.F. Bomber Stations, U.S. Air Force bases.

Norwich                    R.A.F. Sector Operations Centre, U.S. Air Force
                           bases, G.C.I. Stations and Naval Headquarters,
                           Continental communications.

Kelvedon Hatch             R.A.F. Sector Operations Centre, R.A.F. Bomber
                           Stations and R.A.F. Radar Stations.

West Malling               Naval Headquarters at Chatham and Dover.
                           R.A.F Radar and Fighter Conmand Control Centres.
                           Continental communications.

Upavon                     Army establishments in Salisbury Plain.

Sopley and Portsmouth      Naval Headquarters at Portsmouth and Naval Radio
                           Stations at Horsea and Flowerdovm.

Box                        Admiralty establishment at Bath, R.A.F. Sector
                           Operations Centre and Signals Centre.
                           Army signals centres at Cheltenham and Droitwich
                           and Army radio stations.
                           Foreign Office G.C.H.Q. and radio stations.
                           Various Services establishments, including naval
                           bases, important radio stations and miscellaneous
                           radar stations in South-West England, South Wales
                           and the Border Counties.

Map of the United Kingdom showing Backbone and Standby Radio links (1956) taken from CAB 134/1207
Map of the United Kingdom showing Backbone and Standby Radio links (1956) taken from CAB 134/1207