The requirement for an igniter for underwater demolitions purposes arose during early 1944.
The spec called for an igniter that could withstand immersion in 60 feet of water for 15 minutes and a 'worksheet' was approved in September 1944.
After some experimental work final drawings were approved in June 1945.
Contracts for 70,000 to Thrissell's (of Bristol) and 30,000 to ICI were let in July 1945.
It is unlikely that any, other than prototypes, saw service in WW2.
Photos and info © Spotter.