The Kingfisher class was a class of nine patrol sloops of the British Royal Navy built in three groups of three each during the 1930s, that saw service during World War II, mainly on East Coast convoys in the North Sea.

Its small size and short range that this entailed (it was based on a scaled-down destroyer) rendered it unsuitable for open ocean work.

The design had a number of shortcomings, it was designed to too high a standard; constructed to full naval warship specifications and powered by geared steam turbine engines, it was not suitable for mass production and it was armed with only one 4-inch gun forward and depth charges aft, which severely limited their ability to defend themselves, let alone their charges.

The woeful lack of defensive armament was addressed early in the war by adding a multiple Vickers machine gun on the quarterdeck in the Kingfisher and Kittiwake groups, as per the Shearwaters.

Centimetric Radar Type 271 was added on the roof of the bridge as it became available, this was a target indication set capable of picking up the conning tower or even the periscope or snorkel of a submarine.