The trigger is modelled on a Colt 45 Peacemaker pistol.
“There is no big red button with ‘fire’ on it,” said Lieutenant Commmander Woods, whose first name and other details have been withheld for security reasons.
“Knowing what could be on your hands is obviously a heavy load to deal with, but at the same time, the fact that our political masters trust us to deliver the deterrent ... we have to act on the orders of our political lords and masters.
“When you are at sea on a submarine then we don’t the whole story and we have to trust that they know what they are doing.
“The Trident weapons system is ultimately a political weapons system. It is there as a deterrent.
“If we are in the position of launching it then ultimately deterrence has failed. You have to consider the landscape of the UK,” he said.
Lt Cmdr Woods was speaking as British Defence Secretary Michael Fallon said that a nuclear deterrent has never been needed more than in today’s less predictable, more dangerous world.
Mr Fallon underlined the case for renewing the Trident weapons system on a visit to the Faslane naval base on the Clyde, where he received a tour of HMS Vigilant, one of the UK’s four nuclear warhead-carrying submarines.
He said that he hoped a parliamentary vote endorsing the government’s planned renewal programme will take place shortly.
Mr Fallon said: “We have not fixed a date yet but we need to do it, certainly this year, because we need to get on and replace these four boats to ensure the nuclear deterrent can still be provided throughout the 2030s, 40s and 50s.”
Labour leader Jeremy Corbyn this week caused upset by suggesting the country could retain its nuclear submarine fleet but deploy them without their warheads.
The defence secretary said: “That’s like making imitation rifles — those would be pointless patrols.”