The 'Action of 1 November 1944' was a naval engagement between British and German naval forces in the Kvarner Gulf of the Adriatic Sea between the islands of Pag and Lussino (present-day Losinj) (1 November 1944).

The action was fought between a Royal Navy destroyer flotilla and a Kriegsmarine force of one destroyer and two corvettes, the latter deployed to escort a convoy retreating from Sibenik to Fiume (present-day Rijeka). The British destroyed all three of the German warships for no loss to themselves. The action caused the death of more than 200 German sailors. The attacking force rescued 90 German survivors, and 20 German sailors were rescued two days later by German vessels sent to search. The convoy of 19 landing craft, which was expected to be escorted by the three vessels sunk by the Royal Navy, was not intercepted and had reached its destination by 2 November.

After the Italian capitulation of 8 September 1943, the Yugoslav partisans captured most of the Adriatic Sea’s eastern coast in the region of Dalmatia. The Germans rushed to occupy these areas, however, particularly the northern Adriatic ports of Trieste, Fiume (present-day Rijeka) and Pola and established the Operationszone Adriatisches Küstenland (operational zone Adriatic coast), headquartered in Trieste, on 10 September. Since an Allied landing in the area was anticipated, the Operationszone Adriatisches Küstenland also hosted a substantial German military contingent including newly formed German naval units whose sailors manned many captured Italian warships. As result an engagement with the Royal Navy seemed to be inevitable.

In the second half of 1944 the Royal Navy sent a flotilla into the Adriatic, both to secure the area and to attack German coastal shipping. The coastal shipping became increasingly significant for the German forces deployed in the so-called Independent State of Croatia, and especially Dalmatia, as road and railway routes became unsafe for use because of Yugoslav partisan activity. To deny the Germans that maritime option, the Royal Navy initiated 'Exterminate', aimed primarily at the destruction of German corvettes. On 26 October, the Yugoslav partisans informed Lieutenant Commander Morgan Morgan-Giles, commander of the coastal forces in the northern part of the Adriatic Sea, that there were two German destroyers in a cove on the southern coast of Rab island.

The German 'Wikinger' withdrawal from the Dalmatian cities of Zadar and Sibenik to Fiume involved the movement of troops and matériel on a pair of convoys, escorted by Kriegsmarine warships. The withdrawal was a consequence of the imminent capture of Zadar and Sibenik by the Yugoslav partisans. The 'Wikinger II' convoy departed Sibenik at 17.00 on 1 November, and comprised the landing craft Marinefährprahm-522, MFP-554, MFP-484 and MFP-354, representing the convoy’s Gruppe 'A', and 13 combat engineer landing craft (Pionier-Landungsboote) and two large assault landing craft (Sturmboote) arranged into Gruppe 'B'.

In the first part of the route, the convoy was protected by the 2^nd Gruppe of Kapitänleutnant Günther Schulz’s 3^rd Schnellbootflottille, before the escort duty was passed to the Fiume-based escort vessels of Korvettenkapitän Friedrich-Wilhelm Thorwest’s 2^nd Geleitflottille. The 3^rd Schnellbootflottille originally comprised S-154, S-156 and S-158, but on 25 October an attack by aircraft of the Royal Air Force attack, de Havilland Mosquito twin-engined warplanes sank S-158 and damaged S-156, leaving only one operational Schnellboot for the convoy duty. At the time, the only operational vessels of the 2^nd Gelietflottille were TA-20 (ex-Italian 'Urakaze' class destroyer Audace), manned by a crew of 113, and the anti-submarine corvettes UJ-202 and UJ-208 (ex-Italian 'Gabbiano' class corvettes Melpómene and Spingarda each with a crew of about 110), and the fast minesweeper R 187. TA-20 was commanded by Oberleutnant Heinz Guhrke, UJ-202 by Oberleutnant Heinz Trautwein and UJ-208 by Oberleutnant Klaus Wenke.

TA-21 (ex-Italian destroyer Insidioso) remained in port as a result of problems with fuel quality, and this same problem also caused the German force to depart the port at different times. The corvettes left at 16.00, R-187 sailed 30 minutes later, and TA-20 left port at 19.00 with Thorwest on board.

Acting upon the information provided by the Yugoslav partisans, the Royal Navy sortied two 'Hunt Type II' class escort destroyers, Avon Vale and Wheatland, from their base on Ist island at 17.00 on 1 November: Wheatland was commanded by Lieutenant Hugh Askew Corbett, and Avon Vale by Lieutenant Ivan Hall. The escort destroyers were accompanied by the motor torpedo boats MTB-295, MTB-287 and MTB-274, the motor gun boats MGB-642, MGB-638 and MGB-633 and the motor launch ML-494. The escort destroyers were tasked with landing a team of South African coastwatchers on the northern tip of Rab island, and the motor torpedo boats with patrolling the Kvarner Gulf between Rab and Krk islands, while the rest of the British force loitered to the south-west, near Premuda. Morgan-Giles commanded the force.

The coastwatchers were landed at 19.50, the time at which the motor torpedo boats reported the sighting of two German 'destroyers' (in fact the two corvettes) steaming to the south. Using radar, the corvettes detected the destroyers on their port side at 20.15 and came to action stations, while UJ-202 fired two star shells. The crew of R-187 saw this as their vessel followed the corvettes from afar. The destroyers engaged the German corvettes at 20.20 in a position directly to the west of Lun on the island of Pag, assigning a corvette to each as a target. The first British salvoes of 4-in (101.6-mm) shells scored hits on the corvettes from a range of 4,000 yards (3660 m). UJ-202 took several direct hits, which knocked out her single 100-mm (3.94-in) gun, a bow-mounted quadruple 20-mm cannon mounting and a stern-mounted 37-mm gun. Her bridge and radio room were also hit. Even so, she continued to return fire while attempting to head to Rab. UJ-208 was also quickly hit, and her 100-mm (3.94-in) and bow-mounted 20-mm guns were knocked out of action. Her crew managed to put out a fire on her stern, but another blaze amidships blocked all communications between the forward and aft sections of the vessel. By 20.30, she had rolled to port and begun to sink. UJ 202 sank at 21.00.

The Royal Navy force had taken a mere 10 minutes to disable the corvettes. They then began to pull German survivors out of the sea, but the rescue was suspended at about 22.30, when TA-20 was detected on radar and engaged with gunfire. The first salvo hit the German ship’s bridge, killing all officers and knocking out her fire-control system. TA-20 sank close to Pag island. Neither TA-20 nor the corvettes managed to radio news of the attack.

R-187 had maintained radio silence and headed to the east in an effort to evade detection. She linked with the convoy from Sibenik at about 23.45, and proceeded to escort it to the north. Most of the combat engineer landing craft reached Kraljevica, except for two which made port in Senj as a result of poor weather conditions. The rest of the convoy reached Fiume on 2 November. The Royal Navy destroyers steamed back to Ist with empty magazines.

As the weather conditions worsened, the British escort destroyers were able to rescue only 90 survivors from the three German ships. Before the rescue operation was suspended for the engagement of TA-20, Wheatland pulled out of the sea three officers and 68 men, most of them of UJ-202's crew. The Kriegsmarine sortied the corvettes TA-40 and TA-45, as well as S-33 and S-154 to look for survivors, and located 17 men of TA-20's crew on the islet of Trstenik on 3 November. The group included seven wounded men, who were being tended by the local lighthouse crew. Besides them, the ships rescued one UJ-202 and three UJ-208 crewmen from the sea. The deterioration of the weather also prevented retrieval of the coastwatchers for four days. More than 200 Germans perished in this action, including the flotilla commander and all three ships' commanding officers.

Yugoslav partisans had captured Sibenik and Zadar by 3 November 1944, but the war in the Adriatic Sea continued until April 1945. Allied destroyers engaged no large Kriegsmarine vessels in this theatre after November 1944. Dwindling German naval assets in the area resulted in limited action, while the last recorded loss was TA-45 torpedoed by British motor torpedo boats in April. Only four Kriegsmarine ships survived to be captured or scuttled when the German forces in Italy surrendered at the end of April to the advancing forces of the British 8^th Army.