The 1969 film 'Battle of Britain' still has the power to captivate, and it's from this film that we retain enduring images of anxious officers scanning plotting tables as WAAFs moved blocks representing fleets of incoming German bombers and fighters.

Names like North Weald and Hornchurch also linger from the film, which is now closer in time to the year it represents than it is to the present day. Significant sections were filmed at North Weald, and a real wartime hanger was blown up at Duxford for an action sequence of German bombing.

Fortunately for us, visionary people like Air Chief Marshall Hugh Dowding anticipated the danger from air attack, and developed an integrated air defence system, in which Essex played a major part. The focus of this was the trio of fighter bases north of London: Debden, North Weald and Hornchurch, all of which were equipped with spacious hangers, dispersal bays, bunkers and brick built accommodation – a far cry from the flimsy huts which we can still see at Stow Maries World War 1 airfield.

The other missing element at first was modern fighters: it was only last-minute modernisation that gave us the Hurricane and Spitfire instead of the outdated Gladiators, Harts and Furies that served into the late thirties.

North Weald hosted Hurricane squadrons initially, plus Blenheim night fighters. American volunteers arrived with Spitfires, and Norwegian pilots were later based there.

Hornchurch was famous for its three Spitfire squadrons during the Battle of Britain, while Debden had eight RAF squadrons flying from it at its peak.

A critical stage of the Battle of Britain was the attacks on key RAF fighter bases – historians still argue whether or not this might have won the battle for Germany had Hitler not redirected his forces to the bombing of cities in September.

Hornchurch received some twenty air raids during the battle, the worst being on 31 August when six Spitfires were destroyed on the ground or during take-off. Interestingly, one of the most feared dangers was that of ground attack from paratroops: Hornchurch was heavily fortified with pill boxes and other defences.

Debden was attacked several times, with five killed and several buildings destroyed on 2 August. More than two hundred bombs were dropped on North Weald on 24 August, killing a number of people including nine members of the Essex Regiment. A raid on 3 September destroyed buildings, aircraft, hangars and the operations room, killing another five.

In spite of these attacks, few airfields stopped operating for more than a couple of hours – even now, with 'smart' munitions, it is remarkably difficult to disable airfields.

After the war, bases continued to operate into the 1960s, but fast jets were not suited to flying near the burgeoning London civil air traffic, and most were relocated to the coast to intercept a new potential enemy – Russian bombers.

Hornchurch closed in 1962. The airstrips are under the evocatively named new streets, but some remarkable land defences remain for walkers to see. North Weald served until 1958, but is still operating as a civil airfield and has a museum, historic aircraft and some interesting surviving buildings. Debden also has many survivals and remains in military use as Carver Barracks.