'Ouessant', which is also known as the Battle of Ushant or the Battle of Brittany, was a naval engagement between German and Allied destroyer flotillas off the coast of Brittany (9 June 1944).

The engagement took place three days after the Allies' initial 'Neptune' (iii) landings of the 'Overlord' assault on Normandy in north-western France. After a confused engagement during the night, the Allied vessels sank one of the German destroyers and forced another ashore, where she was wrecked.

On 6 June, which was the day of the first Allied landings in Normandy, the remnants of Kapitän Theodor Freiherr von Mauchenheim genannt Bechtolsheim’s 8^th Zerstörer-Flottille, comprising the 'Type 36A' destroyers Z 24 and Z 32, and ZH 1 (formerly the Dutch Gerard Callenburgh) were ordered by Admiral Theodor Krancke, commander of the Marinegruppenkommando 'West', to sail from the Gironde estuary, downriver from Bordeaux in south-west France, to Brest on the western tip of Brittany. The order was intercepted by the British, who detailed Canadian-manned Bristol Beaufighter heavy fighters of RAF Coastal Command to attack the German ships as they passed through the Bay of Biscay. In the attack which followed, the destroyer Z 32 was slightly damaged, but the German ships reached Brest, where Z 24 and Z 32 had their light anti-aircraft armament increased. The destroyers then put to sea again on 8 June in company with the 'Type 1939' class torpedo boat T 24, the sole survivor of Korvettenkapitän Jan-Heinrich Hansen-Nootbaar’s 4^th Torpedoboots-Flottille. The four ships were to head for Cherbourg, where they would reinforce the German positions holding this important port.

The Allies learned of the German intentions through 'Ultra' decrypts, and allotted the task of intercepting the German force in the English Channel to the 10^th Destroyer Flotilla, under the command of Captain Basil Jones in the 'Tribal' class destroyer Tartar. The flotilla’s other ships were Ashanti, Eskimo and Javelin, the Canadian Haida and Huron, and the Polish Piorun and Błyskawica. Jones decided to divide his flotilla: the 19^th Division comprised Eskimo, Javelin, Piorun and Błyskawica, and the 20^th Division comprised Tartar, Ashanti, Huron and Haida.

The British flotilla was steaming to the west down the English Channel when the German ships were detected on radar just after 01.00 on 9 June. Jones turned his force to meet the German ships, which were by now 30 miles (48 km) to the east-north-east of the Ile de Batz. The two flotillas then clashed intermittently, exchanging gun fire and torpedo salvoes. Tartar was struck several times, but was able to put out the resulting fires and restore her speed. ZH 1 was then engaged by both Tartar and Ashanti: the latter launched two torpedoes at point-blank range, and of these one struck ZH 1, blowing off her bow. With the ship crippled, her captain gave the order to abandon ship, then scuttled her with depth charges at 02.40. The captain was among the 39 men killed. Some 28 other men managed to reach the French coast, and the remaining 140 of the destroyer’s crew were recovered from the sea by the British.

Haida and Huron had meanwhile pursued Z 24 and T 24 until the German ships entered a British minefield. The Canadian destroyers attempted to detour round the minefield, but eventually lost contact with the German ships. Z 24 and T 24 regrouped with the intention of returning to engage the British but, on discovering that they were not being followed, departed the area. Haida and Huron returned to the scene and came across Z 32, which had received a heavy pounding and lost contact with the rest of the German force. There was some confusion over identification, but when the Canadian destroyers discovered that their possible opponent was indeed a German ship they opened fire. Z 32 fled at high speed, but after sustaining heavy damage was driven ashore on the Ile de Batz, and then finished by a squadron of Beaufighter strike fighter on the next day.