In message , Graeme Wall
writes
Thay's for USN boats, RN boats have to be in contact with Northwood and
thence to Downing Street. Exactly how they get their launch codes is, for
obvious reasons, not widely advertised. However there is alldgedly a back-up
plan whereby a boat captain can launch on his own initiative if they fail to
get the shipping forecast. The twin key system here is that both he and his
first officer have to enter their own codes in order to arm the launch
system.
I can't comment on that because I don't know anything about procedures,
I just remember the fuss at the time, because it cost us so much and
could not be independently operated.
--
Clive.