The Stickleback-class submarines were midget submarines of the British Royal Navy initially ordered as improved versions of the older XE-class submarines.

They were designed to allow British defences to practice defending against midget submarines since it was theorised that the Soviet Union had or could develop such craft.

[1] The Royal Navy developed plans to use these craft to carry a 15-kiloton nuclear naval mine (based on the Red Beard weapon) codenamed Cudgel into Soviet harbours.

[1] The project was unsuccessful as there were problems finding and paying for the necessary fissile material.

This article about a specific naval submarine of the United Kingdom is a stub.