'Coat' was a British reinforcement operation for Admiral Sir Andrew Cunningham’s Mediterranean Fleet based at Alexandria as one of the six elements comprising 'MB8' (7/9 November 1940).

In overall terms, therefore, 'MB8' comprised 'Coat', 'Crack', the MW.3, ME.3 and AN.6 convoys, and 'Judgement' (i), and in the period 4/11 November involved six naval forces (two fleet carriers, five battleships, 10 cruisers and 30 destroyers) for the protection of four distinct supply convoy undertakings.

The reinforcement was Force 'F' comprising the battleship Barham, the heavy cruiser Berwick and the light cruiser Glasgow from Admiral Sir John Tovey’s Home Fleet in British waters, and the destroyers Encounter, Gallant, Greyhound and Griffin of Vice Admiral Sir James Somerville’s Gibraltar-based Force 'H', of which the latter turned back when the British force was some 190 miles (305 km) from the western tip of Sicily.

The ships departed Gibraltar during the afternoon of 7 November in company with elements of Somerville’s Force 'H' (the fleet carrier Ark Royal, the light cruiser Sheffield, and the destroyers Duncan, Faulknor, Firedrake, Forester, Fortune and Fury [8^th Destroyer Flotilla]), and reinforced Malta en route with two batteries of 25-pdr gun/howitzers, one troop of tanks, 2,150 infantry and the gunners for three batteries of anti-aircraft guns carried in the warships: the personnel numbers were 700 in Barham, 750 in Berwick, 400 in Glasgow and 50 in each of the destroyers.

The stores and vehicles for this Malta reinforcement were delivered in the slightly later 'Collar'.

On 9 November Fairey Swordfish carrierborne single-engined biplane bombers of Nos 810, 818 and 820 Squadrons launched an attack on Cagliari as 'Crack'. On the same day the Italians located the British forces and launched air attacks that achieved only near-misses on Ark Royal, Barham and Duncan.

The Italian response to this far-flung and very ambitious British undertaking was poorly co-ordinated by the Italian air force and Italian navy, the latter under the command of Ammiraglio di Squadra Inigo Campioni. An Italian submarine group comprising Alagi, Axum, Aradam, Medusa and Diaspro was on patrol to the south-west of Sardinia on this day, but found neither of the British forces. The 14a Squadriglia Cacciatorpediniere (Ugolini Vivaldi, Antonio da Noli, Leone Pancaldo and Lanzerotto Malocello), sent to the Sicilian Channel, in fact passed Force 'F', by now detached from Force 'H', during the night of 9/10 November.

Force 'F' joined the Mediterranean Fleet steaming from the east during the morning of 10 November at a point to the south of Malta, and then entered Valletta on Malta to disembark the 2,150 troop reinforcements.

The Italian submarines Mameti, Corallo, Bandiera, Topazio and Capponi were currently on patrol to the east of Malta, but only the last was able to reach the point at which it could launch torpedoes, which missed the battleship Ramillies as she came into Malta with the anti-aircraft light cruiser Coventry, the destroyers and the ships of the MW.3 convoy. On completion of the delivery to Malta, the force departed Malta and resumed its passage to Alexandria.

The one unfortunate result of this successful operation lay in the fact that it convinced the British naval authorities, in both the Mediterranean and the UK, that east/west convoys could with relative impunity be passed through the Mediterranean to reinforce the British forces in Egypt, a conception which subsequent events were to disprove at great cost to the British.