HMS Dianella was a Flower-class corvette of the Royal Navy. She served during the Second World War. The Flower-class corvettes were designed as a cheap and simple multi-role warship capable of being built in the multitude of small civilian shipyards not usually accustomed to building to naval standards. John Lewis, & Sons Ltd, Torry, Aberdeen was such a company that constructed coasters, drifters and cargo vessels. During the Second World War, John Lewis & Sons built more than thirty vessels, including small warships. minesweeper trawlers and patrol vessels; six of these were Flower-class corvettes.