'Reservist' was an Allied unsuccessful attempt to seize vital points in Oran, most notably the harbour and its installations, before the Vichy French could destroy them during the opening stages of the Allied 'Torch' undertaking (7/8 November 1942).

Oran was used by the Vichy French navy as a terminus for coastal convoys, and several French destroyers were present in the harbour. Given the fact that the nearby naval base of Mers el Kébir had been the scene of the British 'Catapult' attack on the French fleet in July 1940, it was to be expected that any failure to secure complete surprise would probably result in bitter resistance to any British involvement.

Two ex-US Coast Guard cutters, renamed Walney and Hartland as British-manned sloops, were selected for the task and flew large US flags as well as the Royal Navy’s white ensign. The landing party comprised mostly US Rangers.

At 02.45 on 8 November Walney and Hartland approached, but the port had been alerted, searchlights were lit, and the French opened fire on Walney, initially with automatic weapons. A loudspeaker announcement in French from the Walney did nothing to reduce the hostility with which the approaching ships were met. At 03.10, partly screened by smoke laid by accompanying motor launches, Walney broke through the boom, but in the harbour she nearly rammed the Vichy French sloop Surprise, which was under way, and was then raked at point-blank range by the sloop. Walney's engines were wrecked, and drifting up the harbour she came under cross-fire from submarines moored to the north and also from Epervier, the destroyer her landing party was to board, berthed alongside to the south. On fire and her upper works a shambles, she drifted round the harbour out of control until, at some time between 09.00 and 10.00, she rolled over and sank. Her few survivors were taken prisoner.

Hartland had already been heavily hit before probing her way through the harbour entrance. Once inside, she too came under point-blank fire from the destroyer Typhon, and was brought to a standstill. After failing to berth alongside a trawler, she drifted into the centre of the harbour and anchored, on fire from stem to stern, yet with hardly a man not killed or wounded. The survivors abandoned ship shortly after 04.00, and after daylight the vessel blew up.

After the destruction of Walney and Hartland, the outnumbered and technically outclassed Vichy French naval, ground and air forces in the area started to fight back against the Allied landing. The destroyers Tramontane, Tornade and Typhon put to sea in an attempt to engage Commodore T. H. Troubridge’s powerful Central Task Force, but the first two rapidly fell victim to the to the accurate fire of the light cruiser Aurora's 6-in (152-mm) guns, after which Typhon sought temporary shelter in harbour. The sloop Surprise tried to cap her success against Walney by attacking Allied shipping off 'Y' Sector, but was sunk by the 4.7-in (119-mm) guns of the destroyer Brilliant. On 9 November, a fresh sortie by Typhon, now accompanied by Epervier, ended with the latter driven ashore in flames and the former beached after struggling back into harbour, both of them victims of the light cruisers Aurora and Jamaica.

The defenders of Oran surrendered on 10 November, and by that time the harbour facilities had been destroyed.