At the outbreak of World War II the Marine nationale (French Navy) needed ships for anti-submarine warfare (ASW) and, following the Royal Navy's example, placed orders from Smiths Dock in South Bank, Middlesbrough, for four ASW corvettes.

Following this the Marine nationale ordered a further 18 ships, to be built at a number of British and French shipyards.

[3] The Fall of France in June 1940 brought a drastic change to these building programmes.

Of the second order, the 12 ships under construction in Britain were taken over by the RN; all were renamed and given Flower names in keeping with the class.

[4][6] These ships, in French and in British service, saw action throughout the Atlantic campaign and performed sterling work.