'Carthage' was the British bombing of the Gestapo headquarters in Copenhagen within German-occupied Denmark (21 March 1945).

A similar raid had been undertaken on 25 September 1942, when four de Havilland Mosquito B.Mk IV twin-engined light bombers of No. 105 Squadron, commander by Squadron Leader G. Parry, attacked the Victoria Terrasse building in which were the headquarters of the Gestapo in Oslo, the capital of German-occupied Norway. The raid was intended to boost the morale of the Norwegian people, and was scheduled to coincide with a rally of Norwegian collaborators, led by Vidkun Quisling.

To reduce the distance they would have to fly, the aircraft were first flown to RAF Leuchars in Scotland, where they were refuelled and each loaded with four 500-lb (227-kg) bombs fitted with 11-second delay-action fuses.

The operation involved a round-trip distance of 1,100 miles (1770 km) and a flying time of 4 hours 45 minutes, and was the longest yet flown by Mosquito aircraft. The bombers crossed the North Sea at an altitude of less than 100 ft (30 m) to avoid interception by German aircraft, and navigated by dead reckoning. Despite their low altitude, the Mosquito warplanes were intercepted by two Focke-Wulf Fw 190 single-engined fighters of the 3/Jagdgeschwader 5 operating from Stavanger. One of the Mosquito aircraft had to make a forced landing in the Oslofjord, and another was pursued by the other Fw 190 until the latter clipped a tree and was forced to break off the attack.

At least four bombs entered the Gestapo building: one failed to detonate, and the other three crashed out through the opposite wall before exploding. The building was not destroyed, but several civilian homes were hit and 80 civilians were killed or injured. The Norwegian government-in-exile, which had not been informed beforehand about the operation, later expressed serious concern to the British government. Official announcements by the German occupation forces claimed that several British aircraft had been shot down, whereas only one Mosquito had been lost.

Although the raid had failed to achieve its primary objective, it was considered dramatic enough to be used to reveal the existence of the new Mosquito to the British public.

Led by Group Captain R. N. Bateson and involving 17 de Havilland Mosquito FB.Mk VI fighter-bombers of Nos 21, 464 and 487 Squadrons as well as one aeroplane of the Film Production Unit, the 'Carthage' raid was launched from RAF Fersfield in Norfolk at 08.40 after the Mosquito crews had been briefed to deliver their attack, at a height of only 100 ft (30 m), on the Shellhaus building, a six-storey unit accommodating the headquarters of the Gestapo in Denmark. It was in this, Danish resistance leaders had reported, that 38 of their operatives were being held on the top floor, and German plans were being completed for a series of mass arrests to paralyse the Danish underground movement.

With an escort of 25 North American Mustang single-engined long-range fighters of No. 64 Squadron, the Mosquito aircraft flew for two hours across the North Sea, making landfall as planned. At about 12.00, and in weather that was now poor, the attackers reached Copenhagen, whose streets were thick with traffic and people. Such was the surprise achieved by the attackers that batteries of German Flak guns, only some 500 yards (460 m) distant from the target, were still covered with tarpaulins.

Bombs from the first wave of Mosquito warplane immediately hit the target building, but Wing Commander P. A. Kleboe was flying so low that he crashed into a flag pole. One crew reported seeing the bombs of the aircraft ahead of them entering the Gestapo building between the first and second storeys. The building was left in flames, many Gestapo personnel were killed, 32 of the 38 prisoners escaped, and the organisation’s records were largely destroyed.

Three other Mosquito aircraft failed to return, one of them crashing tragically into a school building, after one of its wings had hit a lamp post, and causing 86 deaths among the school children. Even so, the attack had achieved its aim. The Mustang fighter force, which suffered two losses to Flak, encountered no air opposition.

On the following day, a reconnaissance aeroplane overflew the target to assess the results. The damage was heavy, with the west wing of the six-storey building reduced to nearly ground level. The Danish underground supplied a photograph showing the building burning from end to end. The raid had succeeded in destroying the Gestapo headquarters and severely disrupting Gestapo operations in Denmark, as well as allowing the escape of 18 prisoners of the Gestapo. Fifty-five German soldiers, 47 Danish employees of the Gestapo, and eight prisoners died in the headquarters itself.