'Chestnut' was a British special forces operation by the 2^nd Special Air Service in support of General Sir Bernard Montgomery’s 8^th Army in Sicily after the 'Husky' (i) landings (12/13 July 1943).

The plan called for two 10-man parties to be delivered into northern Sicily: under the command of Captain Philip Pinckney, the 'Pink' party was to cut road and telephone communications in the north-eastern corner of the island and also to destroy the rail line linking Messina and Catania, while under the command of Captain R. H. Bridgeman-Evans, the 'Brig' party was to attack German and Italian road convoys heading to the south to fight the Allied invasion and also to destroy the Axis headquarters at Enna.

Although it had originally planned that the parties should be delivered by submarine, both were in fact paradropped on 12 July. The two parties immediately encountered difficulties as the 'Pink' party was scattered and suffered damage to its radios and other equipment, and the 'Brig' party landed too close to an urban area with the result that the Axis forces in the area were immediately alerted to its presence and moved to intercept, soon capturing Bridgeman-Evans, who later escaped.

The paradropping of reinforcements was scheduled for 13 July, but as the aircraft could not make contract with either of the original parties as a result of the latter’s damaged radio equipment and returned to base without dropping the additional SAS troopers.

Most of the men on the ground eventually managed to get back to the Allied lines, but neither party achieved anything of real military utility. The operation was not entirely wasted, however, for it provided invaluable experience on how such an operation should not be mounted: the lessons learned were the importance of not changing the plans several times during the last days before their final implementation, of undertaking adequate rehearsal, and of planning so that any party arrived on its drop zone in as tight a pattern as possible so that it could immediately enter action.

This had been the first parachute raid by the 2^nd Special Air Service, and it was also the raid in which Major Geoffrey Appleyard, former commander of the Small Scale Raiding Force, was lost. Appleyard was aboard the aeroplane carrying the 'Pink' team as drop supervisor, but after the drop the aeroplane failed to return to base.