The Handley Page O/100 and O/400 bombers were Britain’s only heavy bombers used during World War One. At the time, the Handley Page was the largest aircraft in the UK. By the end of World War One the Handley Page O/100 and O/400 had nearly proved themselves to be the “bloody paralysers” their original Admiralty remit had demanded of them.


The idea for a long-range bomber had been mooted in December 1914. The head of the Air Department at the Admiralty, Captain Murray Sueter, wanted a bomber that would be able to paralyse the Germans. Aircraft designer Frederick Handley Page took up the challenge, even if he did not have a pedigree for such work.


The Royal Navy’s brief was somewhat stretching. What was wanted was an aircraft that could provide a defence of the coast and naval ports but which was also capable of bombing Kiel, the heart of the German Navy, which housed the German High Seas Fleet.


Parts of the new aircraft were made at Crickelwood and then transported to Kingsbury where it was fully assembled. The completed aircraft was given the serial number 1455 and towed to Hendon for final checks.


The first prototype designed by Handley Page flew on December 17th 1915 piloted by Lieutenant Commander John Babington. The cockpit and the area surrounding the crew were given added protection when compared to other aircraft. Unfortunately this made the aircraft too heavy for the power generated by the engines. There was not enough time to develop a more powerful engine so the only way to solve this was to ditch the extra plating even if it made the crew more vulnerable to gunfire. This became the basis for the first version of the Handley Page bomber – the O/100.


The Royal Navy was the first to procure the O/100 when it established a training school to fly the O/100 at Manston in Kent. It ordered 28 O/100’s for the Royal Naval Air Service. The Royal Flying Corps, realising the value that such an aircraft might have, ordered 12. This was a major success for the Handley Page Company as it had built a few aircraft before 1914 but these had been described as “unconventional”. In the space of 12 months, the idea had gone from thought to paper to actual flight.


The first Handley Page O/100 bombers came into service in late 1916. The Royal Naval Air Service (RNAS) was the first to use them at their base at Dunkirk, France. They were used for night-time raids as it soon became obvious that during the day, they were very vulnerable to German fighter aircraft. As the largest Allied aircraft, they would have appeared to be lumbering giants to much faster German Albatros and Fokker fighters. To start with, the tactic when using Handley-Page bombers was to send them off on a mission individually – to bomb a rail line, a German coastal position or to patrol the sea looking for U-boats. As aircrews became more experienced, this tactic was broadened so that a bombing raid on a German target might include up to 40 bombers.


In something that could have come out of a West End farce, the Germans were effectively given an O/100 by the British. An O/100 was flown to France to start its operational use against the Germans on January 1st 1917 but was mistakenly landed twelve miles behind German lines – the crew had landed in the first field they could see after coming through the clouds. One of the German pilots who thoroughly examined the prize was Manfred von Richthofen. O/100 No 1463 was swiftly painted in the colours of the Imperial German Army Air Service


The O/100 was first used in the anger by the British on the night of March 16th-17th 1917 when a rail yard at Metz was attacked.


The second version, O/400, had more powerful engines and first flew in September 1917. The O/400 was fitted with more powerful engines, a larger fuel tank and was capable of carrying more bombs. By the time war ended in November 1918, over 400 O/400’s had been built and supplied to the War Office.


The O/400 had a top speed of 97 mph and a range of 700 miles. Two Rolls-Royce Eagle engines provided the power and if the weather conditions were favourable, the O/400 could spend eight hours in the air. The O/400 could carry 2000 lbs of bombs. These were either 112 lb or 250 lb bombs carried within the fuselage with two other bombs carried on external bomb racks. However, the O/400 could also carry a single 1,650 lb bomb – the largest in the military’s armoury during World War One.


To ensure that these were delivered as accurately as was possible, the O/400 was fitted with an early bomb aimer – the Drift Sight Mark 1A. For defence, the O/400 was fitted with five Lewis machine guns; two at the front of the aircraft, two defending the rear while one other defended the sides.


When the night-time weather was good, up to 40 O/400’s would take part in raids on German industrial or transport installations. The furthest target from their bases was Mannheim. Such a raid involving forty O/400’s took place against the Saar region of Germany on the night of September 14th – 15th.


By the time the O/400 came into service, the German Air Force was having a very difficult time. The British naval blockade of German ports had led to severe shortages in all areas in Germany – including materials for making aircraft and the fuel to keep them in the air. This made large formation flights of Handley Page bombers more logical as they could be supported by Allied fighter aircraft and a larger number could deliver a much larger payload with consequently greater damage done to the target if it was successfully hit.


The Handley-Page bomber remained in use by the newly created Royal Air Force until the Vickers Vimy bomber replaced it once the war had ended. Those Handley Page bombers that survived the war were invariably converted to civilian use carrying both passengers and airmail.