Otherwise known as the 'Battle of Port en Bessin', 'Aubery' was fought between British commandos and German infantry for the small Normandy fishing harbour of Port en Bessin, to the west of Arromanches, during the first stage of the 'Overlord' invasion of France (7/8 June 1944).

Port en Bessin lies on the coast of the English Channel in what was, in June 1944, the area between 'Omaha' Beach to the west in Major General Leonard T. Gerow’s US V Corps' sector, and 'Gold Beach' to the east in Lieutenant General G. T. Bucknall’s British XXX Corps' sector. An objective the 'Neptune' (iii) assault landing phase of 'Overlord', this fortified port was captured by Lieutenant Colonel C. F. Phillips’s No. 47 (Royal Marine) Commando of Brigadier B. W. Leicester’s 4^th Special Service Brigade.

The port lies close to Blay, the site of a prospective command post for General Sir Bernard Montgomery, the Allied ground forces commander. British petrol and oil storage depots were also to be established under the codename 'Tombola' near the port and for US forces at Ste Honorine, 2 miles (3.2 km) to the west, to be filled from tankers offshore, using buoyed pipelines. The first pipeline into Port en Bessin opened on 25 June.

No. 47 (Royal Marime) Commando embarked on two transport ships for the invasion on 3 June 1944, and these departed the Solent on 5 June. At 05.00 on 6 June, 8 miles (13 km) off the Normandy coast, the commandos were loaded into 14 LCA assault landing craft, which each carried 30 marines and then headed for 'Gold' Beach. The large-calibre German artillery at Le Hamel and Longues was soon able to target the approaching LCAs and opened fire. One LCA was hit and sank: 12 marines were killed or drowned, and another 11 were seriously injured but nonetheless reached the shore. As the other LCAs moved in, they had to cross a wide band of so-called 'Belgian Gates' constructed from steel girders, many of which were tipped with mines. The tide covered many of the obstacles as the LCAs passed over them, preventing the obstacles from being removed by the marines, and four of the LCAs were impaled and sunk by the attached explosives. Some marines swam ashore, but 43 men and much of the unit’s radio equipment were lost.

Mustering on the beach, No. 47 (Royal Marine) Commando had only some 300 men left to it, having lost 28 killed or drowned, 21 wounded and 27 missing. The commandos borrowed a radio from the headquarters of Brigadier Sir A. G. B. Stanier’s 231^st Brigade and set off across country in the direction of Port en Bessin: the marines had been ordered to avoid the 726^th Infanterieregiment of Generalmajor Ludwig Krug’s 716^th Division at Longues sur Mer on the road from Arromanches to Port en Bessin, and therefore moved inland before heading for the port 12 miles (19 km) to the west and linking with Lieutenanbt General Omar N. Bradley’s US 1^st Army as it advanced from 'Omaha' Beach. Early in the evening. No. 47 Commando met German troops at La Rosière, where one commando was killed and 11 others were wounded. German weapons and equipment were taken by the men of No. 47 Commando to replace the equipment which they had lost during the landing. By the time the sun had set, No. 47 Commando had reached Point 72 at Escures, about 1.5 miles (2.4 km) from the port, and here the men dug in and readied themselves to attack the German positions in and around Port en Bessin early on next morning.

The main defences of Port en Bessin were located on 200-ft (61-m) high cliffs known as the western and eastern features, on each side of the hollow in which the port lies. An entrenched and concreted position had been built just to the south of the port on the road to Bayeux, and there were more defences in the harbour. Before the radio set was repaired to arrange covering fire, the marines began a house-to-house battle through the port. The defensive position on the Bayeux road was charged and quickly overcome and its occupants captured. In the afternoon, after a bombardment by the British light cruiser Emerald and three squadrons of Hawker Typhoon single-engined ground-attack fighters firing 60-lb (27.2-kg) RP-3 rockets, the clifftop strong points were attacked and the base of the western feature captured. One troop advanced on the eastern feature against rifle and machine gun fire and grenades thrown down the open slope, which was also mined and had hidden flamethrowers. When the marines were well up the slope, two Flak ships in the harbour opened fire, killing 12 men and wounding another 17. With more than half the troop killed or wounded in just a few minutes, the rest of the British force was forced to withdraw.

German counterattacks overran the commando rear headquarters and an attack across the road linking Escures and Port en Bessin cut off the troop holding Escures. The strength of the commando in the port had by now been reduced to 280 men, many of whom were wounded, but a problematical ammunition shortage was alleviated by the arrival of several members of No. 522 Company of the Royal Army Service Corps, who drove supplies through German machine gun and tank fire. The German defences in the harbour area consisted of dispersed strongpoints, which the marines attacked individually, and gradually the harbour was cleared in a series of costly attacks. The Flak ships continued to fire and ammunition ran low. Captain Terry Cousins led reconnaissance patrol towards the eastern feature and found an undefended zigzag path up to the fortifications at the top. With darkness falling, Cousins led a party of four officers and 25 men up the hill without being seen, and surprised the defenders, who were thrown into confusion. The marines then encountered a concrete bunker, which Cousins and four men rushed. Cousins was killed by a grenade and the men accompanying him were wounded but the German bunker was captured. Outnumbered four to one by the Germans, the marines fought their way up the feature through the concrete, entrenchments, mines and barbed wire defences. The German positions were captured individually, and before dawn the eastern feature had been occupied. The fall of the eastern feature persuaded the remaining Germans on the western feature to surrender. The commandos reoccupied Escures, and at 04.00 on 8 June, the garrison commander and 300 men surrendered.

By 8 June, No. 47 Commando had been reduced to a strength of some 200 men, was ordered to move into the area of Douvres la Délivrande and was then further ordered to move to the east of the Orne river in order to reinforce Major General R. N. Gale’s British 6^th Airborne Division.

No. 47 (Royal Marine) Commando’s losses in 'Aubery' totalled 136 men in the form of 46 killed and 70 wounded.