HMS Sealion (S07) was a Porpoise-class

British Porpoise class submarine

The Porpoise class was an eight-boat class of diesel-electric submarines operated by the Royal Navy. This class was originally designated patrol submarines, then attack. They were the first conventional British submarines to be built after the end of World War II...

 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...

. Her keel was laid down on 5 June 1958 by Cammell Laird

Cammell Laird

Cammell Laird, one of the most famous names in British shipbuilding during the nineteenth and twentieth centuries, came about following the merger of Laird, Son & Co. of Birkenhead and Johnson Cammell & Co. of Sheffield at the turn of the twentieth century.- Founding of the business :The Company...

 at Birkenhead

Birkenhead

Birkenhead is a town within the Metropolitan Borough of Wirral in Merseyside, England. It is on the Wirral Peninsula, along the west bank of the River Mersey, opposite the city of Liverpool...

. She was launched on 31 December 1959, and commissioned

Ship commissioning

Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...

on 25 July 1961.

Sealion was paid off in December 1987 and sold to an Education Trust for deprived inner city youngsters "Inter Action", arriving at Chatham on June 22, 1988.

She was broken up in 1990.