During the First World War the company produced a series of bomber for the Royal Navy to bomb the German Zeppelin yards, with the ultimate intent of bombing Berlin in revenge for the Zeppelin attacks on London. These aircraft included the 0/100, the 0/400 and the four engined V/1500 with the range to reach Berlin. The V/1500 only just reached operational service as the war ended in 1918.
In the immediate post-war years, Handley Page modified a number of O/400's to passenger use, which they flew on the London-Paris route as Handley Page Transport. The V/1500 was considered too large to be practical at the time, but a number of design features of the V/1500 were later incorporated into a O/400 airframe to produce their their first dedicated passenger design, the W.8. In 1924 Handley Page Transport merged with two other regional airlines to create Imperial Airways, England's first national airline service. Handley Page developed several large biplane airliners, including the luxurious Hannibal, for use on Imperial routes.
Handley Page also paid for the development of what soon became known as the Handley Page Slat (or slot), a small channel cut into the leading edge of the wing to improve airflow at high angles of attack. The design was so successful that licensing fees to other companies was their main source of income in the early 1920s.
With the spectre of the Second World War looming, Handley Page turned back to bomber design, and produced the Hampden, which took part in the first British raid on Berlin. In response to government request for heavier, longer ranged aircraft Handley Page produced the Halifax which after the Lancaster was the most prolific British heavy bomber, and considered by some to be to a superior aircraft.
After the war the British government sought tenders for jet bombers to carry Britain's atomic bomb. The three types produced were known as the V-Bomberss, and Handley Page's contibution was the Victor, a four engined cresent winged design. This aircaft remained in service (as a tanker aircraft) well beyond the demise of the company which created it.
Aircraft Designs (chronologically):