[1][2][3] She was converted to an escort carrier in the Atlantic Basin Iron Works at Brooklyn New York and commissioned into the Royal Navy on 6 May 1942, under the command of Captain Conolly Abel Smith.

Propulsion was provided by four diesel engines connected to one shaft giving 8,500 hp (6,300 kW), which could propel the ship at 16.5 kn (19.0 mph; 30.6 km/h).

Eventually believed ready for sea, she left the dock on 15 May but had to return to rectify an engine problem.

Leaving Nova Scotia for Britain on 14 June, she again suffered from engine problems which cast her adrift for three hours while they were repaired.

Arriving at Greenock on 23 June, she entered dock for modifications and to lengthen her wooden flight deck.

The two escort carriers—joined by the fleet carrier Victorious—left for Greenock on 16 October to join the British forces taking part in the North Africa landings Operation Torch.

The force comprised the battleship Rodney, the carriers Argus and Dasher, the light cruiser Delhi and nine destroyers.

Flying operations began on 8 November 1942, but after a Sea Hurricane crashed into her bridge Biter was temporarily put out of action.

The destroyer dispatched to investigate could not find anything, then at 16:25 a Swordfish sighted a U-boat on the surface only 8 mi (7.0 nmi; 13 km) from Biter.

Two Martlets which until now had been idle took part in a patrol but lost the convoy and had to ditch beside a straggling merchant ship which rescued the crews.

[11] Ordered to close with the convoy by the Commander-in Chief (C-in-C) Western Approaches bad weather prevented any flying until after 16:00 on 10 May.

The Swordfish responded to a sighting of a U-boat on the surface dropping two depth charges but was hit by anti-aircraft fire from the submarine.

A second Swordfish had taken off to assist but could not find the U-boat or the convoy in the bad weather and was forced to ditch beside a straggling merchant ship.

It was because of these last engagements that aircraft were ordered to fly in pairs, they were forbidden to fight it out with surfaced submarines and only to attack if it was diving.

[13] On 13 May, the convoy had come within range of RAF Coastal Command Consolidated Liberators and Short Sunderlands.

Two Swordfish took off at dawn and discovered two surfaced U-boats, which were attacked by a patrolling Sunderland of No.423 Squadron RCAF from RAF Castle Archdale.

With HX 237 now under land-based aircraft cover, the C-in-C Western Approaches ordered Biter and her escorts 200 mi (170 nmi; 320 km) south, where the eastbound convoy SC 129 was being threatened by a gathering wolfpack.

Homing beacons were to be fitted to all carriers together with a Type 237 blind approach beam system for use in poor visibility.

The Flotille 3FB equipped with Douglas Dauntless dive bombers served on the ship between 1945 and 1949 during several campaigns in French Indochina.