In June 1944, the Germans began launching thousands of pilotless V-1 "flying bombs" with 1,000kg (2,200lb) warheads towards London from the French and Dutch coasts. .
Codenamed "divers" by the Royal Observer Corps, the pulse jet powered weapons flew at an altitude of about 1,000m (3,300ft) but at an average speed of 550km/h (340 mph). Shooting them down was difficult and dangerous.
At 22:40 (10.40pm) on 23 June, which was around sunset in the wartime double summer time, Spitfire pilot Ken Collier of 91 (Nigeria) Squadron RAF had exhausted his ammunition firing at one – so he flew his Spitfire XIVc alongside and literally tipped it over with the end of his wing.
The squadron's operations record book noted: "F/O K. Collier brought into effect a new method of destroying divers when, after running out of ammunition, he flew alongside of it and with the wing of his aircraft he tipped the diver over causing it to spin in."
Other pilots were discovering they could achieve the same result by flying close enough to overlap wingtips so their airflow alone upset the V-1's stabilising gyro and tumbled it into the ground – but in practice very few fell to these extraordinary methods. Between June 1944 and the following March almost 4,000 V-1s were shot down, mostly by aircraft and by anti-aircraft guns on the ground. Nevertheless more than 2,400 got through, killing more than 6,000 people.