In 1939, the Hawker design staff had studied alternative powerplants for the Hurricane. However the modifications required for the fitting of the Rolls Royce Griffon or the Bristol Hercules would most certainly lead to a reduced production rate at a time where a steady flow of aircraft into operational RAF-service was absolutely essential. In February 1940, the new two-stage supercharged Merlin XX, initially producing 1,185 hp (868 kW), was proposed. This engine had been designed for mass-production and became available only weeks later. On 11 June 1940 the first Hurricane with the Merlin XX, P3269, made the first flight. In August 1940 the Merlin XX achieved full production status. The first Hurricanes with the new Merlin XX were designated Mk.IIA Series 1, and differed only slightly from the earlier Mk.I. The aircraft retained the Mk.I wing with eight 0.303in (7,7mm) Browning machine guns.

Enter the Hurricane Mk.IIC...
The Hurricane Mk.IIC was introduced in June 1941 and had the Browning machine guns replaced by four 20mm Hispano II cannon. As with the Mk.IIB, the new wing of this version allowed the ability to carry two 44-gallon fuel tanks and two 250lb or 500lb bombs.
Eventually the Hurricane Mk.IIC would become the most widely used version, with over 4,700 aircraft built, the majority of them by Hawkers at Langley.

Two Hurricane IICs remain in active service with the Battle of Britain Memorial Flight at RAF Coningsby.
LF363 is currently in the markings of No.1 Squadron Hurricane I P3395 'JX-B as flown by F/L Arthur 'Darkie' Clowes in August 1940 from RAF Collyeston/Wittering.
On 11 May 2021 PZ865 returned from a major overhaul by the Spitfire Company at Biggin Hill in an all-black intruder c/s as worn by Hurricane BE634 of No.247 Squadron as based at Predannack and Exeter in 1942. This unit was tasked on defensive night fighter patrols in the Plymouth and Exeter area as well as offensive night intruder and 'Roadstead' operations over north-western France.