Handley Page believed that his aircraft designs would be more marketable if they were able to carry a passenger, and this resulted in the design and development of the Handley Page Type E. This was of a similar design to the Type D, but larger. The Type E's increased-span crescent wing was braced by two kingposts, and the mainwheel skid was shortened and a conventional tail skid introduced. It was powered by a Gnome rotary engine. The seating was for two in tandem, with the pilot at the front and, like the rebuilt Type D, the Type E (H.P.5 in the 1924 system) was finished in yellow, which also gained it the name Yellow Peril, resulting in a degree of confusion that has continued over years.
When the Type E was first flown in April 1912, it proved to be the first truly successful Handley Page design, but was slightly damaged by an inexperienced pilot in October of the same year. An improved fin was introduced while the repairs were being carried out, and the machine's flying career was resumed on 1st February 1913. In April, a new wing was introduced, which used ailerons instead of wing warping for lateral control.. This remarkable monoplane went on to fly many thousands of miles and carry several hundreds of passengers before being converted to a single-seater for school use in mid-1914. Requisitioned at the outbreak of World War 1, it was found to be unsuitable for service use and was not flown again.
An 'improved' Type F had been developed from the Type E to take part in the War Office Military Trials of 1912. This aircraft, designated H.P.6 in the 1924 system, differed primarily by having a revised tail unit, side-by-side seating for pilot and observer and a 70 hp Gnome rotary engine, but was also strengthened considerably for its intended military role. It was first flown on 21st August 1912, but this aircraft's brief career was dogged by ill-fortune, terminating in a fatal accident on 15th December 1912 when both occupants were killed.