§ Mr. Denzil Daviesasked the Secretary of State for Defence how the inflation index, as mentioned in paragraph three of the letter of 11 March 1982 from the United States Secretary of Defence to the Secretary of State for Defence, (Cmnd. 8517), will be determined in respect of the total contribution to be paid by the United Kingdom to research and development of the Trident II system.
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§ Mr. BlakerWe shall be discussing with the United States authorities the detailed implementation of the agreements set out in Cmnd. 8517. The basis for the inflation index will be agreed in these discussions.
§ Mr. Cryerasked the Secretary of State for Defence if he considers that an additional number of Russian SS20 missiles will be deployed to balance the Trident D5 missiles it is proposed to deploy as a replacement for Polaris; if so, if he will estimate that number; and if he will make a statement.
§ Mr. BlakerThere is no direct correlation between the numbers of Soviet SS20 missiles, 300 of which have already been deployed, and the modernisation of the United Kingdom strategic nuclear deterrent force by the replacement of Polaris by Trident. The SS20 is an intermediate range land-based missile, and represents only one of a large range of Soviet nuclear capable systems, including both land and sea based missiles and aircraft, able to strike the United Kingdom. The United Kingdom Polaris/Trident force represents only a very small fraction of the nuclear weapons deployed by the Soviet Union. It is a last resort strategic deterrent capable of posing a threat of unacceptable damage against the Soviet Union in the event of an attack against us. The force of four submarines represents the minimum number necessary to maintain one boat on continuous patrol.
§ Mr. Cryerasked the Secretary of State for Defence if the Trident D5 missiles will be targeted on cities or military targets.
§ Mr. BlakerIt has been the practice of successive Governments not to disclose the targeting plans for our nuclear forces.
§ Mr. Cryerasked the Secretary of State for Defence by how many times the Trident D5 missile fleet will be more powerful than the Polaris fleet currently deployed.
§ Mr. BlakerThe operational capability of a nuclear delivery system is dependent on a number of factors, including numbers and yields of warheads, range and ability to penetrate enemy defences. The comparative "power" of different systems is not a concept which has any precise meaning. A comparison between Polaris, which came into service in the 1960s, when no anti-ballistic missile defences existed, and Trident which is due to enter United Kingdom service in the mid-1990s and last well into the next century, would thus be misleading.
However the British Trident submarines will have sixteen missile tubes, as have the Polaris submarines. The number of missiles to be carried and the number of warheads per missile will be matters to be decided by the Government of the day.
§ Mr. Cryerasked the Secretary of State for Defence if he will describe the improved accuracy of the Trident D5 missile over Polaris; and why he considers such accuracy necessary.
§ Mr. BlakerIt is not the practice, for security reasons, to reveal the detailed operational characteristics, including accuracy, of weapon systems. Paragraph 31 of defence open government document 82/1—"The United Kingdom Trident Programme"—makes it clear that the increased accuracy of the Trident D5 system played no part in the Government's decision to opt for this system rather than the earlier C4 variant.