In late 1920, Handley Page started design of a new single-seat torpedo bomber to meet the requirements of Air Ministry Specification 3/20 for a carrier-based aircraft to replace the Sopwith Cuckoo, in competition with the Blackburn Dart.

The resulting design, the Type T, (later known as the H.P.19) and named the Hanley was a single-engine biplane of wooden construction.

[2] Initial testing revealed that performance was disappointing with low speed handling, and that the view from the cockpit was also poor.

[3] After being damaged in a crash landing, the first prototype was rebuilt with new wingtips, a revised two-bay wing and with the control cables for the elevators enclosed in the rear fuselage to reduce drag, flying in December 1922 as the Hanley Mark II.

[4] By the time that the Hanley Mark III was available for testing, the Dart, which was developed from Blackburn's earlier Swift, had already been ordered into service.