Longer-term deterrent options and the limits on French cooperation

Chevaline and Poseidon were treated as near-term answers while a working party considered longer-term deterrent arrangements. The alternatives included land, seabed, surface-ship, and space-based systems, with air-launched options examined separately. An air-breathing cruise missile was viewed more favourably than an air-launched ballistic missile, but that proposal was also dropped. Cooperation with France faced a mismatch in development schedules because the French first-generation system was only entering service. Adopting Poseidon would add restrictions on disclosing information supplied by the United States. The author connects British interest in French cooperation with the effort to enter the Common Market, while explicitly acknowledging that the surviving file does not state that motive.