It is 81 years since the Battle of Britain took place.
Although its peak is officially regarded at 15 September, British and German records suggest 18 August 1940 was the hardest fought day in the battle.
On that day, the Luftwaffe flew 850 sorties involving 2,200 aircrew, while the Royal Air Force responded with 927 sorties involving 600 air personnel.
British aircraft had to ensure they refuelled and rearmed as often as they could, with some pilots having to fly several sorties each day.
On 18 August, the Luftwaffe attempted three large raids in the space of a few hours, targeting a number of airfields in the south of England, including those at Kenley, Biggin Hill, Gosport, Ford, Thorney Island, Hornchurch and North Weald, plus a radar station at Poling.
Robin Brooks works at Biggin Hill Heritage Hangar, a restoration facility dedicated to putting Spitfires back in the air.
"The 18th August 1940 was absolute carnage here – at half past twelve, 300 German aircraft crossed the channel, crossed the coast," he said.
"The skies over Kent were completely darkened with these massive armada of aircraft.
"About 500 bombs were dropped on the airfield making it look like a giant colander – there were craters absolutely everywhere."
Fighting was fierce throughout The Hardest Day, although the final wave of German aircraft were unable to reach their targets.
Aircraft engineer, Alex Monk, explained how difficult it would have been for pilots to hit their target at such high speeds.
He said: "You're aiming for like this tiny little spec going 300 miles an hour that way, and you're trying to shoot that airplane down and especially if he's not flying in line with you, you've got to put a lead time on it, almost like if you were clay pigeon shooting,
"You aim for the clay, but you don’t aim atthe clay, you aim ahead of it. Imagine that but on steroids."
"Not the easiest thing to go and do," he added.
Mr Brooks said Number 32 Squadron flew Hurricanes and Number 610 Squadron flew Spitfires.
"Our aircraft, luckily, had been scrambled earlier on, so they were up there at a height ready to come down onto the Germans," he said.
"As the armada came in from the south… our aircraft managed to come down between them and the Germans actually lost 110 aircraft."
During the fighting, the RAF and Fleet Air Arm lost 68 aircraft, including 31 in air combat, while 69 German aircraft were destroyed or damaged beyond repair.
The Germans were particularly confident in the capabilities of one aircraft, the twin-engined Messerschmitt Bf110, but the British Hurricane and Spitfire proved to be too much and six Bf110s were lost on The Hardest Day.
Nine German Dornier 17Z aircraft were involved in a low level attack of RAF Kenley on 18 August, suffering heavy casualties with four destroyed, two seriously damaged and the rest sustaining minor damage.
"We had the superior aircraft, we had the superior pilots, our structure, our fighter command structure, how we operated, how we got into the air, how we had radar which gave us advance warning of the German’s crossing the channel," Mr Brooks said.
At the end of the day, out of 40 men, eight were killed, five taken prisoner, three returned wounded and seven found floating in the English Channel.
Cover image: An aerial battle over London during the Battle of Britain (Picture: PA).