In 1939 the Royal Navy suffered its worst ever submarine disaster just 40 miles from where it was built in Birkenhead.

During the maiden voyage of Thetis - the pride of the Royal Navy - 99 men tragically lost their lives - not through battle, but through an unfortunate accident.

Inside Out joins a Liverpool theatre company as they prepare to stage a new play based on the story of the ill-fated submarine, Thetis.

In the summer of 1939 a major rescue operation to save the lives of 99 men trapped inside a submarine came to an abrupt and pitiful end.

For three days, in the heart of Liverpool Bay, just 38 miles from land, the men on board battled the effects of carbon dioxide poisoning, waiting for a rescue which never came.

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