THE United States of America was the main arsenal of the "Free World" during the Second World War and many thousands of aircraft were supplied to its Allies. Great Britain took considerable numbers, both by outright purchase or on a lend-lease basis. Less well known is Britain's supply of over 1000 aircraft and gliders for use by the USAAF, practically all in the European and Mediterranean Theatres of War (НТО and MTO). In the main, this involved three combat types and an assault glider which were employed in Operations for which comparable US designs were not available. Spitfire XIs and Mosquito XVIs were used for fast high-altitude photographic work over Europe. Beauflghter Vis were used in the MTO for night-fighting duties until replaced by P-61 Black Widows, and Spitfire V, VIII and IX models equipped early fighter units and tactical reconnaissance units before Mustangs were received. The USAAF in the United Kingdom also received some two hundred training and communication aircraft from the RAF in the absence of American types—which did not arrive in any numbers until the spring of 1944. A few communication types were also acquired in the Middle East and Far East but on a very temporary basis. Other British designs, usually single examples, were acquired for lest in the USA and technical evaluation. Generally, the original camouflage finish was retained by all these aircraft during their American service although there were many interesting variations.