Film on the importance of mine countermeasures vessels (MCMV) in modern warfare, beginning with an introduction by Sir Bernard Miles from the deck of the cruiser HMS Belfast (C.35), moored on the Thames.
The film looks at the mine threat during the First World War and how the Royal Navy attempted to counter it using the Royal Naval Trawler Reserve. German developments in mine warfare during the Second World War are discussed before moving on to modern mine warfare. Ton Class minesweepers are shown exercising at sea, sailors train at the shore establishment HMS Vernon and HRH Prince Charles is shown arriving onboard the Ton Class minesweeper HMS Bronington (M.1115) which he commanded at the end of his service in the Royal Navy. The use of sonar in minehunting is discussed, Royal Navy vessels are shown participating in the international taskforce that cleared the Suez Canal of munitions following the 1973 Arab-Israeli conflict and Prince Charles brings HMS Bronington up the Thames, passing under Tower Bridge and mooring on the river for a visit by the Queen and Prince Phillip. The film concludes with a brief look at the future of mine warfare, including the use of glass-reinforced plastic in MCMV construction and remote controlled vehicles in mine disposal.