US nuclear deterrent was used to defend Hong Kong

Papers distributed to the Prime Minister Harold Macmillan in 1961 - and released by the national archives this week - show that military chiefs were concerned they could not hold the British colony by means of conventional warfare if China decided to take the enclave by force.

British officials decided to seek clandestine assurances from the Americans that their plans for the outbreak of war between the West and the Communist bloc would involve a nuclear strike to protect Hong Kong.

In February 1961, the Foreign Secretary Sir Alec Douglas-Home said in a letter to Macmillan: "It must be fully obvious to the Americans that Hong Kong is indefensible by conventional means and that in the event of a Chinese attack, nuclear strikes against China would be the only alternative to complete abandonment of the Colony.

"In these circumstances it is perhaps not so much formal talks with the Americans that we need so much as an informal exchange of views involving a discussion of the use of nuclear strikes."

It was pointed out by military planners that Hong Kong was particularly vulnerable, not least because its water and food supplies, from the mainland, could be cut off at any time.

Another memo to Macmillan said: "Hong Kong is no longer of vital strategic interest to us. But it has symbolic and political importance and is our only direct frontier with the Communist world."

Sir Alec continued: "We should encourage the Chinese to believe an attack on Hong Kong would involve nuclear retaliation."