But in December, one British airmen decides to try a new trick; bombing at night. Aircraft are already having to contend with strong air defences – modified artillery guns make life difficult for spotter planes flying at their normal altitude, while machine guns and rifle fire are a danger closer to the ground. But at night attacking planes will be far less visible, and theoretically in much less danger. Wing commander Charles R Samson has already made history, becoming the first British pilot to fly an aircraft from a ship in 1912. Now he climbs into his French-made Farman biplane, and takes off to bomb German targets in the occupied Belgian city of Ostend. The Farman has an open cockpit and the flying suits of the time gave little protection form the bitter cold.

“This would have been difficult as navigation by night had been given little consideration at this point in the war,” says Mahoney. “It was, as with so many aspects of early aviation, experimental.”

Samson recounted his raid in a newspaper article written years after the war. “Now and then I used the pocket flashlamp in my breast pocket to glance at the dials and gauges. After a long while the Farman climbed to 5,000ft and as the Germans had all their lights burning, I could easily pick out Ostend and Zeebrugge.” The Farman glided into the city, the streetlights burning on the roads below. “While I toured calmly above the roofs, gunners flung shell after shell into the night. Men dashed that way and this, and then one of their own searchlights lit up a battery of big guns. The target of a lifetime!” Samson dropped his bombs and then evaded furious German fire to return to base. The night skies had become a weapon themselves, a cloak of darkness to hide aircraft.

1 April 1915: The first fighter plane scores its first victory

In the daylight, meantime, aviators are struggling to find new ways to turn their lumbering wood and canvas aeroplanes into hunters. Air combat is a haphazard affair, with pilots having to manoeuvre their aircraft so their observer could shoot, or they could use a machine gun firing above the arc of their own propeller; a difficult feat to achieve while also flying a plane. The ultimate aim is to mount guns firing forward – the pilot only had to “aim” the plane, making it much easier to shoot down enemy aircraft. But in order to fire the guns they have to be within the pilots reach – and that meant they have to fire through the propeller, with potentially disastrous results as they were made of wood. “The challenge of firing through propellers had been considered as early as 1912 but remained a problem until 1915,” says Mahoney.