'Mailfist' was a British unrealised plan by Admiral the Lord Louis Mountbatten’s South-East Asia Command for the recapture of Singapore from December 1945 (spring/August 1945).

The operation was to have used the forces of Lieutenant General O. L. Roberts’s Indian XXXIV Corps, namely Major General D. C. Hawthorn’s Indian 23^rd Division, Major General F. J. Loftus-Tottenham’s 81^st (West Africa) Division and Brigadier C. R. Hardy’s British 3^rd Commando Brigade.

During the early months of 1945 the South-East Asia Command developed plans for the liberation of the British colonies of Malaya and Singapore from the Japanese, who had seized them between December 1941 and February 1942. The plan called for the 'Zipper' amphibious assault in October 1945 in the areas of Port Swettenham and Port Dickson in north-western Malaya by two divisions and one brigade. 'Mailfist' was to be undertaken once the 'Zipper' lodgement was secure, using an additional two divisions and one brigade that were to be landed as soon as possible after 'Zipper'. This force was then to advance to the south through Malaya and retake Singapore. As Singapore was heavily protected, the forces scheduled to reinforce the British East Indies Fleet in late 1945 included the monitors Abercrombie and Roberts, each carrying two 15-in (381-mm) guns, to bombard the island’s defences.

It was planned that 'Mailfist' would be launched December 1945 and be completed in March 1946, and another offensive, 'Broadsword' (ii) for the recapture of northern Malaya, was to be conducted at the same time as the advance towards Singapore.

The USA opposed all these plans for the liberation and Malaya and Singapore on the grounds that the shipping and other resources required for the campaign would reduce the numbers available for the planned 'Downfall' invasion of the Japanese hone islands. The British believed, however, that it was necessary to liberate Singapore as early as possible on both military and political grounds.

Following the Japanese surrender, 'Zipper' was both scaled down in size and brought forward in time, and was undertaken early in September 1945 for the speedy liberation of Malaya. 'Mailfist' was not conducted, but instead replaced by 'Tiderace', in which an Allied naval force transported troops and equipment directly to Singapore for the unopposed reoccupation of the city early in September.