by James Jinks
Unacceptable damage
1. As we point out in Part I of the study, in attempting to define an effective deterrent, we must make assessments of probable Soviet attitudes which cannot be founded on precise data. The judgements made by the super-powers about the scale of damage which they need to threaten against each other are no guide to our own requirements, since the scale of deterrence is related to the gains foreseen by the potential aggressor, and the gains from eliminating the United Kingdom would clearly be less than those from eliminating the United States. There is in our view no unique answer as to what would probably constitute unacceptable damage. Some of the options may be preferred as being more likely than others to make the Soviet Government reappraise its intentions. But the choice must weigh cost and other aspects.
2. It has been UK policy not to say exactly how we would use our nuclear capability: the Soviet Union itself is left to draw its own conclusions from what it can see of the capability. We assume that this policy will be maintained. There is little practical risk of the Soviet Union’s so misreading the scope and character of the capability that deterrent value would be lost; and our target options need not therefore be constrained by the problems which would arise if we had to make our intentions public.
3. We believe that a deterrent threat of unacceptable damage might be posed in one or both of two potentially overlapping but distinct ways:
a. if the general level of destruction likely to be suffered by the Soviet Union was such as to outweigh the benefits from removing the UK from the international scene and/or appropriating her resources
b. if the damage were likely to undermine, at least for a considerable period, the Soviet Union’s ability to compete across the whole range of her capabilities as a super power with both the United States and China.
4. Broadly, our deterrent might be designed to threaten capabilities of key importance to the Soviet state; or cities as a whole; or a combination of the two. The extent to which threatened damage against particular capabilities and/or against cities might be perceived as unacceptable by the Soviet leaders is discussed in detail in Annex A; our judgement is that they would find unacceptable:
a. the disruption of the main Government organs of the Soviet state;
or
b. grave damage to a number of major cities, involving destruction of buildings, heavy loss of life, general disruption and serious consequences for industrial and other assets.
5. In order to illustrate this judgement, we have identified three broad options for creating damage which, compared with the gains from aggression against the United Kingdom, would be considered by the Soviet Union to be unacceptable. Possible future Soviet defences against strategic attack are considered in Part III of the study. But to illustrate the possible implications of these options for the characteristics of a future ballistic missile force (while not ruling out a non-ballistic solution), we have placed them in the context of current assessments of Soviet Anti-Ballistic Missile (ABM) defences. As to the total Soviet ABM capability we have assumed continuing SALT I restrictions. Current assessments suggest that the Soviet Union may in future have the capability for the endo-atmospheric close defence of the Moscow area as well as for the exo-atmospheric defence of a much wider area around Moscow (as in the current GALOSH system).44 For illustrative purposes, we have assumed a coverage for the exo-atmospheric system based on the observed performance of GALOSH (shown in map at Annex B). But the development of a longer range missile providing ABM cover over more cities cannot be ruled out. (Part III of the study discusses the technical feasibility of such a development, and the implications of alternative judgments on this point).
6. We have identified three broad options for creating unacceptable damage:
(1) Option 1 would be to threaten disruption of the main Government organs of the Soviet state. It would require the capability to penetrate ABM defences (both endo- and exo-atmospheric) and to destroy hardened targets. On the assumption that a British strategic force would be used only after a period of tension, and probably only as a retaliatory strike, we must assume that the Soviet Government would have implemented protection measures against nuclear attack. In order credibly to threaten disruption of the Government, we would therefore need to be believed to be capable of destroying the main government centre (both above and below ground) within the Moscow outer ring road and, outside it, a selected number of alternative bunker locations which are associated with the centralised system of command and control of the Soviet Union at national level (see paragraph 1 of Annex A). Attack on the Governmental capability would additionally carry with it widespread destruction of Moscow as a city and in the area around Moscow thus enhancing the deterrent value of this option. (As it would be necessary to ground burst the nuclear weapons targeted against the bunkered centres, the threat posed would include a significant hazard from residual fall-out.)
(2) Option 2 would be to threaten breakdown level damage to a number of cities including Moscow. It would require the capability to penetrate both endo- and exo-atmospheric ABM defences, but not that needed to destroy hardened targets. We do not believe that to threaten breakdown-level damage solely to Moscow as a city (leaving the Government capability probably seriously impaired but still functioning) would constitute unacceptable damage. We believe it would be necessary to threaten breakdown-level damage to Moscow as a city (defined as the area within the outer ring road) and Leningrad and two other large cities. A capability on this scale could threaten damage beyond repair to nearly half the buildings in four major cities of the Soviet Union and the possibility that more than 5 million people might be killed and a further 4 million injured. It would involve the destruction of the Soviet capital and the centre of the Soviet bloc, of cities which are major centres of military research, development, and production (RD and P), and of areas within these cities which are of major importance for Russian history and culture.
(3) Option 3 would be to threaten damage to a number of cities, but excluding Moscow. It would require neither the capability to attack hardened targets nor, on current assessments, to penetrate ABM defences (see paragraph 10 above). We believe that the option would constitute unacceptable damage if it threatened either of the following:
(a) to inflict breakdown-level damage on a significantly larger number of cities than under Option 2, which effectively lie outside the present Moscow ABM defences. The cities which might be selected are illustrated in the map at Annex B which shows all cities west of the Urals with a population of more than 500,000 people (numbered in terms of their population) and the limit of ABM coverage. We believe that the selection of cities for targeting under this option should be based primarily on population size, but should also take account of military RD and P facilities, industrial importance, and of historical and cultural importance. We therefore consider the cities chosen should include Leningrad which is of major importance in all these respects. For the remainder of the ‘package’, (while taking account of any limitations imposed by the range of the delivery vehicle) a wide geographical spread might be chosen to heighten the threat of psychological shock and nationwide dislocation. As to the number of cities to be threatened, we believe that this should be calculated to put at risk a broadly similar total number of people as under Option 2. This would require attacks on Leningrad and about 9 other major cities;
(b) to inflict grave damage not necessarily to breakdown level on 30 major targets, including Leningrad and other large cities and possibly selected military RD and P targets (such as submarine building facilities), which effectively lie outside the present Moscow ABM defences. The major impact of a threat of this sort would be in terms of general shock and dislocation plus the risk to sensitive military facilities not associated with major cities.
7. We believe that any one of these options would constitute an unacceptable level of damage. Option 1 would, in our view, inflict a greater penalty than the others, involving as it would both large scale civilian destruction and
very severe damage to the government capability; and it would therefore provide greater certainty of deterrence. It may, however, be more difficult and expensive credibly to threaten damage of this sort since it would involve the ability both to penetrate endo- and exo-atmospheric ABM defences around Moscow and to destroy structures hardened against nuclear attack.
8. As between Options 2 and 3, the former has the advantage of involving the destruction of Moscow as a city, with inevitably some resultant effect on the working of central Government. It is also arguable that if the Soviet leadership believed that we were content permanently to abandon any attempt to penetrate the Moscow defences, there might be a distinct reduction in the psychological effect of our deterrent since, for the first time since we attained nuclear status, there would be an important part of Western Russia which was free from the risk of our attack. These considerations would need to be weighed against the advantages of a package under Option 3 which includes a larger number of cities and which might avoid a requirement to penetrate the ABM defences around Moscow.
9. These three major options (and the alternatives indicated within Option 3) clearly do not exhaust the possibilities; they are intended only to illustrate levels of threat which would be sufficient for our purposes. In our judgement, if UK capability fell short of meeting one of these options or its equivalent there would be room for significant doubt about its adequacy.
Independence
1. We believe that to satisfy the key purposes identified in paragraph 4, we must retain sole national control over the order to fire our nuclear weapons. (This would be qualified only to the extent of our present arrangements for consultation with other members of the Alliance if time permits.) This view carries implications for possible co-operation with another state or states in the procurement and maintenance of a strategic capability. We must be able to sustain our capability nationally for a period of time, to guard against the risk that a partner might seek to neutralize our capability for independent action by cutting off his support during a crisis. A judgement cannot be reached in isolation from the cost and other considerations, but we believe we should aim to be able to maintain an independent capability for a period of at least a year.
Other Criteria
1. We have also considered the other major criteria for the characteristics of a strategic nuclear capability. These are discussed in Annex C. For the reasons stated there, we believe a UK capability should:
(a) offer a high assurance that it will survive a pre-emptive attack;
(b) preferably be continuously deployed at early readiness to fire;
(c) offer a substantial probability that the full damage threatened would be achieved. We believe that an aggressor would be deterred if there was a one in two chance that the threatened damage would be achieved in full (and a higher probability of some lesser damage).45
The CDS’s Duff–Mason file also contains two maps, the first of the Moscow region; the second of the anti-ballistic-missile screen that Chevaline was designed to penetrate; the trajectory of a Chevaline missile fired from a Royal Navy Polaris submarine in the Faroes area of the North Atlantic; and the information that the yet-to-be fitted Chevaline warheads and decoys are ‘designed to give 50% probability of attaining the number of penetrations needed in order to achieve the existing damage criterion when facing an exo-atmospheric ABM defence …’46
Jim Callaghan convened a meeting of his ‘Restricted Group’ nine days after the Duff–Mason Report was circulated. The Prime Minister upped the pace of its work not just because Duff–Mason was now available but because he was due to meet the US President, Jimmy Carter, at the Guadeloupe quadripartite summit (US, UK, France and West Germany) in the Caribbean in early January 1979. This would present an opportunity to sound Carter out about the possibility of extending Nassau and the Polaris Sales Agreement to cover a possible British purchase of the C4 Trident missiles the United States was planning to fit to its new ‘Ohio’ class submarines.
The Cabinet Secretary, John Hunt, briefed Callaghan to this effect on 20 December 1978, the day before the ‘Restricted Group’ was to meet:
the only decision required now is whether the stage has come when there should be talks with the Americans. It is very difficult to take the study any further without knowing what co-operation from them we can get, their view on the cost of the various options, etc. If Ministers agree that there ought to be such talks, they could best be initiated by your talking to President Carter at Guadeloupe.47
Hunt used a minute from David Owen to Callaghan circulated the day before, pressing the case for further study of the cruise-missiles-on-hunter-killer-submarines option which, wrote Owen, ‘is intrinsically more attractive than the officials’ paper [Duff–Mason] allows’, to give Callaghan his (Hunt’s) views on the next-generation UK deterrent.48
If the group thinks there is merit in Dr Owen’s arguments further work can of course be done on the options he advocates. I have however myself considerable doubt about a bargain basement deterrent. The case for having a British independent deterrent is not an overriding one but rests on a balance of arguments. If however we are to have one, it has to be credible both to ourselves and our potential enemy. If it is not so credible, it would be better to do without it. This does not mean that it has to have the ability to destroy Moscow. Indeed, I would not recommend going for Option I in the criteria study. It does however mean the assurance of creating other unacceptable damage.49
The MOD was also sceptical. In a letter sent to the Private Secretary of the Defence Secretary, Fred Mulley, on 18 December 1978, Michael Quinlan, the Deputy Under-Secretary of State, Policy, at the Ministry of Defence, described Owen’s arguments as ‘unexceptional’ and ‘superficial’ and argued that an effective deterrent required ‘options an order of magnitude higher than this’ of up to 10 million dead. The Soviet Union’s ‘threshold of horror’, he wrote, was different to the UK’s because it had lost more than 20 million people in the Second World War. ‘In this field nothing is provable, but it is far from clear that they would regard less than half of 1% of their population as an unthinkable price for contemplating a conquest of western Europe,’ wrote Quinlan. ‘Still more to the point, it is far from clear that they would rate highly the probability that a country would choose incineration rather than subjugation in order to inflict a strike of such relatively modest proportions.’ The UK had to possess the ability ‘to run the whole course right up to unacceptable strategic damage – to finish what we start’, argued Quinlan.50
Mulley put in his own paper too, on 20 December 1978, in response to Owen’s of the previous day. The ‘concept of small packages of cruise missiles on existing SSNs has further implications which we should note’, he wrote:
Once we get away from a ‘dedicated’ force, we are in effect changing other criteria as well as the damage criteria – we break away from year-round readiness, we increase vulnerability (because boats have other things to do besides hide), we may increase reaction time (because boats may be in the wrong place for firing and out of communication). In addition, we detract from the other and very important roles of the SSN – the pattern of deployment and operation for the strategic deterrent roles is incompatible with that for the existing roles. We have none too many SSNs now for these roles, and I note the Foreign and Commonwealth Secretary’s view that we should have more. His proposal would have the opposite effect unless we built more boats – which in logic should then, as the paper by officials notes, be charged to the deterrent role.51
Mulley also stressed that the cruise missile option would seriously affect the undetectability – and hence the invulnerability – of the UK deterrent as ‘for technical reasons about forty minutes must elapse between salvoes. The chance of CMs penetrating to the target – already a matter of some concern unless one is in the business on the United States’ scale – would not be improved by coming at the defences in penny packets. In addition, the submarines themselves would be more vulnerable, since t
he first salvo would disclose their positions.’52
The meeting in No. 10 on the morning of Thursday, 21 December 1978, opened with Jim Callaghan explaining that the Duff–Mason teams had ‘been asked to advance the completion date of the study so as to give Ministers a chance to consider it before the Guadeloupe meeting’.53 There was more thought on the general uncertainty in the world in the thirty years to 2009–10, including the notion of a Britain standing alone and in serious peril. John Hunt’s minute records the ‘standing alone’ contribution to the 21 December discussion like this:
we could not rule out the possibility that within the timescale we had to consider we might find ourselves having to face alone Soviet political pressure or military threats. In this situation a British deterrent would provide us with the basis for resistance.54
Short of that desperate last contingency, Britain’s remaining a nuclear-weapons power was seen as a stabilizing factor ‘particularly in relation to Germany, and also as a balance to France, who would otherwise remain the only nuclear power in Europe’.
Tony Duff’s politico-military assessment for the Callaghan Group was that for the next 30–40 years (i.e. up to 2009–19) ‘UK deterrent planning need not be geared to any nuclear threat beyond that posed by the Soviet Union … [and that] [w]e should base our policies on the assumption that much the same adversary relationship will continue with the Soviet Union as we have today.’55 But among the ministers in No. 10 that morning there was at least one who sensed just how precarious were their and everybody else’s predictive powers: