Once production of the Spitfire Mk.I was underway, an improved version was looked at based around the 1175hp Merlin XII. The Spitfire Mk.II, or Supermarine 329 as its constructor named it, was born. Great hopes were placed in this new version as an order for 1000 aircraft was placed on 12 April 1939, before the mark's first flight, for serials P7280 - P8799. This production run was launched at Castle Bromwich in Birmingham, the new Supermarine production line. The first aircraft were delivered in June 1940 and the Spitfire Mk.II included all improvements and refine¬ments added to the Spitfire Mk.I. Deliveries continued up to July 1941. The Mk.II entered service, in the midst of the Battle of Britain, first with 66 Squadron and progressively, the Spitfire Mk.II became standard equipment across Fighter Command with no less than 56 squadrons known to have been equipped, fully or partially, with the mark. Peak usage was reached during the summer of 1941, but, from the autumn of that year, it began to be withdrawn from first line units in favour of the Mk.V. Among the squadrons equipped with the Spitfire Mk II, there were the squadrons manned by men coming from Southern Rhodesia (266 Squadron), Australia (452 and 457 Squadrons), Canada (401, 403, 411, 412, 416 and 417 Squadrons) New Zealand (485 Squadron) and from the USA with the famous Eagle Squadrons (71, 121 and 133). Illustrated with 30 photographs and seven colour profiles. Revised September 2022.