The H2S equipment so far discussed had been manufactured at EMI and RPU on a crash programme basis, limited to 200. The main production was scheduled to commence in May 1943 and it was evident that because of the high priority attached to H2S this would be the main source of 10 centimetre equipment for some time. The prospect of the availability of large numbers of the H2S system had other consequences which first affected me during the tension of the March 1943 events at Chivenor.