There is renewed interest, in 2009, in the US and China ratifying the Comprehensive Test Ban Treaty (CTBT) in 2010–11. It is therefore relevant to look back on the debate over this question in 1977–79.

On 1 December 1977, the Prime Minister, James Callaghan, called a meeting with the ministers who managed policy on nuclear weapons. I attended as Foreign and Commonwealth Secretary along with the Chancellor of the Exchequer, Denis Healey, and the Secretary of State for Defence, Fred Mulley. We discussed whether the UK should be associated with the US and the USSR in the proposed separate agreement on verification, the so-called Inner Track. This was to be in addition to the UK's participation in the multilateral arrangements which would apply to all the parties to a CTBT. It was decided to seek more information about the costs and other implications and meet in the New Year. I was in favour of participating.

Following a memo from the Cabinet Secretary, Sir John Hunt, dated 20 March 1978 (Document 27), we agreed, in principle, that the UK would participate, a decision helped by the Americans telling the UK government that they would not expect the UK to contribute to the capital or overhead costs in connection with the separate agreement. The UK would only meet its own personnel costs and the cost of modifying our own teleseismic stations (the costs were estimated at £1 million capital costs and a little under £0.75 million annually). This arrangement was facilitated by Cy Vance.