'ST' (i) was a British four-part naval undertaking to intercept and destroy German coastal shipping (14/20 January 1940).

On 14/15 January the destroyers Glowworm, Grenville and Greyhound of the Harwich-based 1^st Destroyer Flotilla, together with the minesweeping trawlers River Clyde, Stella Leonis and William Wesney, swept along the Dutch coast during the night in 'ST1'. Two Dutch and one Swedish ship were stopped, but were allowed to continue after inspection. Two Danish steamers, the 1,321-ton Svanholm and 1,944-ton Knud, were sent to the inspection station in the Downs escorted by River Clyde. At 22.50 the 619-ton German vessel Phaedra was captured by Greyhound off the Dutch coast near IJmuiden after being sighted by William Wesney. The vessel was renamed Empire Sentinel for British service, and in 1943 was taken over by the Royal Navy for use as a wreck dispersal vessel and renamed Rampant.

On 15/16 January the destroyers Grafton, Griffin and Free Polish Błyskawica undertook the 'ST2' night sweep off the Dutch coast, with fire support provided by the destroyers Jackal, Janus, Javelin, Jervis, Juno and Jupiter. Grafton sent in the 3,204-ton Latvian vessel Rasma for inspection.

During the night of 19/20 January, 'ST3' was undertaken off the Dutch coast by the destroyers Grenade, Grenville and Griffin, together with the escort vessel (ex-destroyer) Whitley, and these sent in for inspection two Dutch, one Norwegian and one Swedish ships.

During the same night the 'ST4' operation was undertaken by the destroyers Glowworm, Grafton, Greyhound and Free Polish Błyskawica, which sent in for inspection one Norwegian and one Swedish ship.

The four 'ST' operations therefore involved the destroyers Błyskawica, Glowworm, Grafton, Grenade, Grenville, Greyhound and Griffin, the escort vessel Whitley, and the anti-submarine trawlers Arkwright, Cape Melville, Edwardian, Milford Princess, Pyrope, River Clyde, Stella Leonis, Stella Rigel and William Wesney.