The Royal Navy has a fleet of four Vanguard-class submarines – Vanguard, Victorious, Vigilant and Vengeance which form the UK’s Trident nuclear programme.

At any time there is at least one sub hidden beneath the waves and the commander of each vessel has a secret order he hopes he will never have to carry out for it can mean only one thing, there is a nuclear war raging above the surface.

If the vessel cannot make contact with the UK and the captain believes
the Government has been wiped out he will walk to an area of the sub that is off limits to everyone but a select few.

There he will find a locked safe containing the British Prime Minister’s letter of last resort. The document has never been seen by anyone only the serving PM as it is burned at the end of each premier’s term of office.

The document carries the instructions to the commander on what to do if the UK comes under nuclear attack and the Government is gone. Such is the secrecy surrounding this doomsday letter it is held in a safe within a safe in the bowels of the massive sub which, if needed could stay submerged for four years.

There has been much criticism of the massive amount spent on the UK’s Trident programme which has only two purposes, deterrence or total destruction.

At all times one of these 15,000 tonne vessels will be wandering the seas aimlessly deep beneath the waves waiting for an event the world hopes will never happen.

Only a handful of military commanders know any sub’s location, indeed most of the crew are totally unaware of the 150-metre vessel’s position.

After the Queen appoints a new British Prime Minister one of his first tasks is to write the letter of last resort.

Tony Blair‘s cabinet secretary has revealed the former Prime Minister went “quite white” on being told of the options open to him when compiling the
document. In the event of a nuclear strike on the UK the commander will be faced with the horrendous task of pushing the button that would lead to the deaths of tens of millions of people.

Before he would make that decision the commander would have been out of contact with his superiors for a considerable time as well as making a series of other checks.

One of the more bizarre and quintessentially British checks being the requirement on the sub’s crew to try to tune into the Today programme on BBC Radio 4 for several days.

The assumption being if the BBC had gone off the air then civilization has broken down in the UK.