A total of 344 Hamilcars had been built when production ended in 1946.
Hamilcars were only used on three occasions, and only in support of British airborne forces.
Because it had already developed the Hotspur, which first flew in November 1940, and was considered to have a sufficiently developed production capacity capable of producing a larger glider, General Aircraft Limited were chosen to develop X.27/40.
There was a great demand on the specific types of wood required to build the glider, and difficulty in finding suitably large airfields with enough skilled personnel where the gliders could be constructed and stored; it also appears that a lack of official priority and poor management at GAL also impeded production.
Between March and August 1942 GAL had promised eighteen Hamilcars would be built and delivered, but by September only one had actually appeared; this slow rate of production so concerned the Ministry of Aircraft Production that it appointed an 'Industrial Panel' of three senior industrial experts to visit GAL and detail the causes of the problems.
Production for the glider was targeted to begin in late 1941 with approximately 40-50 to be completed by the end of that year; in reality this was overoptimistic, with the planned 40-50 only being completed by June 1944.
The slow rate of production for the Hamilcar appears to be the result of a combination of factors.
By the beginning of 1941, the War Office had issued four specifications for military gliders to be used by the airborne forces.
The first was Air Ministry specification X.10/40, which called for an eight-seater glider similar to the German DFS 230, which eventually became the General Aircraft Hotspur I; the second was specification X.25/40 which became the Slingsby Hengist, a fifteen-seat glider; the third was specification X.26/40, the 25-seater Airspeed Horsa; and the last, X.27/40 was for a glider that could carry a light tank or other heavy loads.
The Hamilcar was transported to RAF Snaith in Yorkshire, as GAL's airfield at Hanworth was too short for the glider to take off from; moving the glider to a secure military airfield would also ensure that it remained secret.
Its first flight was conducted on 27 March 1942, towed by a Handley Page Halifax bomber.
A second prototype was completed in June 1942, and further testing and development took place at a number of different airfields, including the Airborne Forces Experimental Establishment at RAF Beaulieu; all flight trials appear to have been successful, and there were few differences between the prototypes and the production models.