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NSA AND THE ZIRCON PROJECT 439
missiles were either replaced or upgraded, they would most
likely be defeated by Moscow's anti-missile defences, rendering
Britain's independent nuclear deterrent implausible. The ability
to hit Moscow was considered to be the key criterion for an
effective British deterrent. 4 Throughout the early 1970s British
defence chiefs pressed for the purchase of a new American
missile called 'Poseidon', with mUltiple warheads powerful
enough to overwhelm Soviet defences. One of the reasons they
wanted to buy American was because they had always recognised
that 'Without US intelligence support any nuclear deterrent
system wou.ld lose credibility in a few years.'5 In other
words, access to American sigint was vital for targeting British
nuclear weapons.
However, Britain's political leaders had recognised that there
would be a diplomatic furore if Britain bought Poseidon. The
country had just entered the Common Market and the French
would certainly not appreciate such a public reaffirmation of
the 'special relationship' at this crucial moment. Accordingly,
in late 1973 the Edward Heath government rejected the Poseidon
option and chose a British programme to update and improve
the ageing Polaris missiles, code-named 'Chevaline'. At the time,
officials believed that this code name was French for a nimble
mountain goat. In fact, when the Chevaline saga unravelled
some years later in the House of Commons, it turned out that
its true meaning was either someone who sells rotten horse
flesh, or an ugly woman. There was considerable humour at
the government's expense. 6
Britain's defence scientists were delighted by the Chevaline
decision, which effectively gave them their own mini-space
programme and a substantial secret budget for advanced science.
Some defence intelligence experts were less impressed. Louis
Le Bailly, Director General of Intelligence at the Ministry of
Defence, was working closely with the CIA, and enjoyed the
best insights into the Russian anti-ballistic-missile systems which
Chevaline was supposed to defeat. He was not optimistic about
its chances: 'I personally laboured with my advisers for the best