They dined on fillet of beef washed down with fine wines, staged ribald theatrical productions to help break the monotony of lurking for months in the depths of the ocean and looked forward to weekly “familygram” bulletins from home.

The extraordinary, secret, sometimes bizarre life of the men who spent months at a time onboard Britain’s Polaris nuclear deterrent submarines is being revealed in a new exhibition at the National Museum of the Royal Navy.

Exhibits range from the intriguing – including an officers’ mess menu and play programmes – to the thought-provoking and downright scary, such as a training model of a Polaris missile and the keys that would have been used to unleash the weapons, each with a range of 2,800 miles and an explosive power eight times that of the atomic bomb dropped at Hiroshima.