The Vickers Wellesley originated from Air Ministry Specification G4/31 which called for a general purpose aircraft capable of bombing, reconnaissance and army co-operation. Designed by Barnes Wallis using geodic construction, a Vickers Type 253 bi-plane won the G4/31 contest and in 1935 an order was placed for 150 machines. Meanwhile, Wallis was working on a monoplane, the Type 246, using the same construction techniques and this took to the air for the first time in June 1935. It soon became clear that the monoplanes performance was significantly better that that of the biplane and in September 1935, the Type 253 order was replaced with one for 96 Type 246s to fulfil a light bomber role. After a number of improvements, the first production aircraft, the Wellesley, took to the air in January 1937 and entered RAF service with No 76 Squadron at Finningley in April of that year. It went on to equip a total of 6 Bomber Command squadrons in the UK.
The Wellesley had a crew of 2, was powered by a Bristol Pegasus XX radial engine of 925 hp and featured a manually operated retractable undercarriage. Its armament comprised a Vickers .303 in forward firing machine gun in the starboard wing and a Vickers K machine gun in the rear cockpit. It was capable of carrying a 2,000 lb bomb load.
Five aircraft were modified to carry 3 crew members and equipped with a more powerful Pegasus XXII and extra fuel tanks for work with the RAF Long Range Development Flight. On 5th November 1938, 2 of the 3 aircraft that set out flew non-stop for 2 days from Ismailia, Egypt to Darwin, Australia (7,160 miles) to set a world distance record. This epic flight remains the longest by a single engined aircraft.
By the outbreak of the Second World War, Wellesleys had been retired from the UK units but continued to serve with 4 squadrons in the Middle East. As such they were heavily involved in the East African campaign against Italian forces in Eritrea, Ethiopia and Somalia from June 1940 until the last Italian-held town in theatre was taken by Allied forces in November 1941. Thereafter, one squadron carried out maritime reconnaissance duties over the Red Sea until the end of 1942.
Egypt and South Africa also operated the Wellesley. A total of 177 were built and there are no known survivors.