HMS Sterlet was a Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 S-class

British S class submarine (1931)

The S-class submarines of the Royal Navy were originally designed and built during the modernisation of the submarine force in the early 1930s to meet the need for smaller boats to patrol the restricted waters of the North Sea and the Mediterranean Sea replacing the British H class submarines...

 submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 which was launched 22 September 1937 and fought in the Second World War

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. Sterlet is one of 12 boats named in the song Twelve Little S-Boats. So far she has been the only ship of the Royal Navy to be named Sterlet.

On 8 April 1940 Sterlet left for a patrol in the Skagerrak, Norway under the command of Lt. Gerard Henry Stacpoole Haward, aged just 30, and the husband to Diana Auriol Haward. Four days later she unsuccessfully attacked a convoy of three merchant ships and a destroyer. The following day she was assigned a new patrol area and on 14 April torpedoed the German gunnery training ship Brummer

German minelaying cruiser Brummer

Brummer was a minelaying cruiser of the German Kriegsmarine during World War II .-Design:In the mid 1930s two artillery training cruisers were built to drill the gunnery personal of the Kriegsmarine...

, leading to it sinking the following day.

She was possibly sunk by the German anti submarine trawlers UJ-125, UJ-126 and UJ-128 on 18 April. Alternatively, she may have struck a mine whilst returning to port.