Some info on the RN fifth Polaris sub and later Poseidon option

uk 75

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27 September 2006
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A recent book releasing British nuclear discussions by Peter Hennessy throws
some clear answers to often asked questions:

Why did the RN not get the fifth Polaris boat?

After much discussion the new Labour Government in 1964 decided
that the Polaris fleet was too worthwhile to cancel. Two subs were already being built and too much had been spent on the third to cancel it. In order to meet the objections of the strong anti-nuclear lobby (not just CND but also some military and the Treasury who thought the deterrent was a waste of money) the fifth boat, due to be ordered in January 1965, was an easy

Did losing the fifth boat make much difference?

Papers show that the 4 boats were sufficient to keep one on station
at all times, sufficient for the UK's NATO commitment. A fifth boat
would have made operating the fleet easier and cheaper. It would also
have added a safety margin if one had been lost at sea. On the whole a bad decision, but politically necessary.

What was the fifth boat going to be called?

There seems to be no evidence anywhere to support the name "Ramilles"
often quoted. Unlike the CVA 01 it never got as far as being named.

Why did the UK not get Poseidon?

The Heath government in 1970-74 was keen to get Poseidon but was told
by Kissinger that Congress was not likely to give agreement. This was against the background of the poor relationship between the Administration and Congress but also to strong hostility in Congress to the Northern Ireland
situation. The UK Treasury continued its earlier opposition to further

Would Poseidon have been the best option?

Undoubtedly. The UK would not have had to embark on the expensive
Chevaline programme. US and UK submarines would have remained compatible
in firing options (confusing the Russians) for longer. Trident could have been
ordered somewhat later in the 80s (though sub life was a driver as well)

UK 75
Mention of the book here
It would have been an old capital ship name, so I'd say it would be unlikely. Ranger has historically been a name for a small vessel, a gunboat or escort rather than a capital ship. The other R-class battleships were Royal Oak, Royal Sovereign and Ramillies, so I think one of these would be a likely bet. The final R-class battleship was to be named Resistance, so that's another possibility.

Thanks for the namecheck. I rather like "Resistance". "Ramillies" would have looked odd as the other names all began with "Re". In a novel written
in the 60s the author Chapman Pincher invented his own names for the
R class: Retribution, Resolve, Retaliation, Reprisal. One option originally looked at was 8 boats with fewer missiles on each.

UK 75
Richard Aldrich's 'GCHQ' offers a few insights into Chevaline before going into the Zircon project. He firmly lists Chevaline as a failure.

He puts the decision not to eventually buy Poseidon and instead develop Chevaline as a move to avoid "reaffirmation" of the Special Relationship just at the time the UK joined the EEC. This sounds a little too simple to me, even developing Chevaline implied extensive US support.

He quotes COS (71) 41st meeting 30/11/1971 that "Without US intelligence support any nuclear deterrent system would lose crediblity in a few years." This means that US Sigint was vital to targeting Polaris and this quote alone raises issues about how independent Polaris really was relying on the UK/USA intelligence agreements to remain an effective weapon system.
He goes on to say that Louis de Bailly, Director General of Intelligence at the MOD was working closely with the CIA and that he "enjoyed the best insights into the Russian anti-ballistic-missile systems which Chevaline was to defeat." He spent six months trying to convince the JIC that Chevaline wasn't capable enough for the job. Senior scientists persudaded the Cabinet Secretary to withdraw the reports from circulation and in protest he resigned in July 1974. Chevaline was just too important to go ahead whatever the costs or implications. I suppose even if they had cancelled Chevaline in the 70s what else could Britain do to maintain its deterrent system? They had no other options past 1974-75. Aldrich puts the final cost at £800 million and states that it was test-fired but failed to work.
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