Therefore a temporary ' factory' was set up in three purpose-built tents measuring 120ft by 80ft. Inside the 'factory', supervisor Ken Softly and his construction team set about building Hurricane and Spitfire fighters, using moulds cast from Spitfire V BM597 and Hurricane IIC LF751. A good number of these replicas would meet a fiery end during the film's bombing scenes. Most were pure static facsimiles, but some were fitted with motorcycle engines to turn the propellers. These examples would be towed by wires into bomb craters or exploded while 'taxying' on screen. Ken and his crew even produced a full size CASA 2.111 , used in the Heinkel crash scene, in which the crew is being rescued after a belly landing back in France. This sequence is reported to have been shot in the fields at the back of Pinewood Film Studios.

These instances led to some of the RAF contingent issuing an unofficial set of 'Pilots Notes', which were rapidly circulated around all those on the 'set' with a sense of humour!

Another avenue would have to be explored in order to get Stukas into the film. Once again Vivian Bellamy's expertise in replica building was called upon.

As time went on the Ministry of Defence realised that Spitfire Productions could safely operate the fleet of vintage aircraft in their control, and permission is reported to have eventually been granted to restore the real Stuka to flying condition. Sadly this revelation came too late for the film, as it would have taken up far too much money to instigate the restoration of the Ju 87, and it would never have been ready in time to meet the filming schedule, so the Stuka remained on the ground.

"God's teeth, take cover!" - Kenneth More

While preparations were being made to welcome the aerial unit back from Spain, there was much to be done behind the scenes. John Wilson Apperson, the film's wardrobe manager, was in the process of having up to 2,000 costumes made for the actors and actresses to wear. Ron Baker, one of the production's 'props men' managed to acquire a dozen Spitfire and Hurricane gun sights and a stock of Spitfire main wheels. A security company was contracted to carry out guard duties at the film's main airfield locations, in the expectation of many hundreds of onlookers, who could not only endanger themselves during

the forthcoming bombing scenes, but could actually get in the way of air-to-ground photography.

With the large numbers of vintage aircraft being employed in the film, it was obvious that a support organisation would be a major requirement in keeping all of the fighters and bombers serviceable. While John 'Tubby' Simpson and his engineers would, with the benefit of hindsight, work absolute wonders, a consortium of companies from Britain's aircraft industry was 'seconded' for extra back-up. Indeed, a large-scale technical team had been built up to coordinate and oversee the production, as well as a number of British and German technical advisors.

During the time while the aerial unit were in Spain, the film's major 'stars', in the human sense of the word, were being 'called up' for duty and were in the studios filming the interior scenes for the movie. The interiors were a mixture of real locations and recreations; the latter specially built at Pinewood. The early pre-credits scene in the film, where Dowding (Sir Laurence Olivier) walks down the long passage en-route to the lift which serves Sir Francis Stokes' (Harry Andrews) office, was shot in the Ministry of Defence buildings in Whitehall, London. The lift attendant was played by 69-year-old Edward Williams, a role he took in real life. This short scene was filmed on a quiet Sunday morning, so that the film crew would not disturb the workings of the 'powers that be' at Whitehall in their day to day tasks.

Other interiors had to be painstakingly re-created for the cameras. Air Chief Marshal Dowding's office at Bentley Priory was pieced together at Pinewood, using period photographs and the help of Dowding's one-time right-hand man, Robert Wright. Air Vice Marshall Keith Park's (Trevor Howard) main operations room was another which had to be built especially for the production. Some of the actors with smaller roles (Nigel Patrick, Sir Michael Redgrave etc) were able to complete their scenes for the film in a matter of days, whereas the more major players were involved for a lot longer, especially those who had airfield sequences as well as interior scenes to film.

"Don't just stand there, get one up" - Robert Shaw

In an unprecedented move, three corridors of the sky above East Anglia and the Midlands were allocated to the film company by the Military Air Traffic Organisation for the duration of shooting. Each of these measured 50 miles long by ten miles wide. NOTAMS (Notices to Airmen) were issued when filming was to take place which in effect cleared these corridors of any unwanted aircraft.

At the end of the Spanish filming a roster was drawn up at Tablada as to which pilots would be flying the Messerschmitt 109s for the British sequences. The following Spanish Air Force pilots were granted limited periods of leave of absence from their military duties: Pedro Santa Cruz Barcelo, Ramon Guiterrez Martinez, Jose Manuel Alvarez Coterillo, Eladio Ramos Gutierre, Jose Mingot Garcia, Fernando De Artega Danvilla, Jose Antonio Garcia Perez, Julio Arrabal Teran, Jesus Fernandez Trujillo, Carlos Diego Garcia-Bermudez, Fortunato Lanzaron Olmos, Francisco Alvarez Redono, Manuel Cabello Arcas, Francisco Meseguer Garcia, Camillo Vazquez Herjas and Pedro Nieto Matrinez. Wilson Connie Edwards, from the Confederate Air Force in Texas, and Vivian Bellamy in England would accompany these pilots for the flight to England.

May 14, 1968, dawned cold and windy. It was hardly good conditions to welcome the flying unit from Spain. The Heinkels, Messerschmitts, Spitfire and Mitchell had taken five days to fly from Tablada to Duxford, initially landing at RAF Manston in Kent to clear customs, and if this was the sort of weather the film unit would have to put up with in the UK, then things did not look too good for keeping the production on schedule. One Heinkel and a Messerschmitt were stuck in Jersey after suffering taxying accidents on landing, but the rest of the fleet made it to Duxford, after some confusion which saw the formation orbiting over the City of Cambridge. A Spitfire and Hurricane from the RAF's Battle of Britain Flight at Coltishall, plus one of the film's two-seat Spitfires, had earlier launched out of Duxford in order to welcome the 'Luftwaffe' to Britain, which was indeed a portent of things to come.

With a strong crosswind that day at Duxford, there were a few' dodgy' moments as the tired pilots brought their aircraft in to land, but all got down safely and were battened down for the night in readiness for the aerial dogfights to come.

"Don't you yell at me, Mister Warwick" - Susannah York

As with the Spanish shooting, the film unit was dogged with bad weather in England during the summer of'68. During late May the French airfield scenes were being shot at the south-western end of Duxford, where the film company had built an impressive-looking chateau. Tents, vehicles and ancillary equipment surrounded this facade, completing the illusion of an Allied Expeditionary Force airfield in northern France at the time of Dunkirk.

While the ground scenes were relatively easy to put 'into the can' the schedule was delayed when it came to filming the Hurricanes taking off. The rain had rendered the grass area on that side of Duxford Airfield unusable and this meant several days of waiting around for the grass to dry before any filming

could take place. This scenario of the filming schedule being dictated by the weather conditions had a critical effect on the film's finances, and on more than one occasion Harry Saltzman had to fly out to United Artists in the USA in order to negotiate extra cash for the production.

Almost every day, the pilots, groundcrews, cameramen, and all the other technical personnel needed to operate the vintage aircraft fleet, would arrive for briefing at 8am, the sorties of the day would be planned and agreed, the aircraft would be warmed up, only to have the clouds roll in and put a stop to any flying activities for the whole day. This happened time and time again during May, June and July.

The days when the weather was set fair, it was a 'maximum effort' to get as much aerial footage filmed as was humanly possible. Duxford Airfield came alive as the Spitfires, Hurricanes, Messerschmitts and Heinkels, plus the B25, got airborne and headed off over East Anglia for the filming corridors in the sky. Around an hour later they would all return and the sortie would be debriefed. Sometimes during the evening the previous day's footage, the 'rushes', as they are known in the film industry, would be viewed by the director, producers and pilots over in Duxford's former camp cinema.

Luckily we managed to attain a fairly good aircraft serviceability record during filming, recalled Hamish Mahaddie. I originally had allowed for one aircraft "to be lost each week, and at the end of the filming schedule we would have no aircraft left. But due to the sheer hard work and determination by Tubby Simpson and his engineers we kept the fleet going right up to the end.

We had very few real spares we could turn our hands to, so if for instance we had a radiator problem, Tubby would whip it off the aircraft and tear off to Delaney Galley, the radiator specialists, who would fix it overnight, and the radiator would be back on the aircraft by late morning the following day. Trouble was, Tubby was the sort of person who could not really delegate work, and he ended up doing most of it himself. He sadly died shortly after we had finished the film and I'm sure that it was due to the very high workload shouldered by him in keeping all the aircraft flying.

The unenviable task of keeping all of the aircraft under control on the ground and in the air at Duxford fell to Squadron Leader Ron Chadwick. It was his job to see that the laws of the air were obeyed at all times, and it was no mean feat to cope with the vagaries of some 30-plus vintage aircraft on a day to day basis. On the grounds of safety, no low level beat ups were authorised, although some did inevitably take place by some of the more exuberant pilots when they returned from filming sorties.

The British Board of Trade had issued the Messerschmitts and Heinkels with restricted permits to fly, which enabled them to get airborne for the purposes of aerial filming and moving location only. With the exception of the aircraft operated by the RAF's Battle of Britain Flight, this meant that the film's aircraft fleet was not allowed to take part in any air displays during the months of production.

"We either stand down or blow up, which do you want?" - Michael Caine

Surprisingly accidents during filming were few and far between. One of the Messerschmitts, C4K-61 (G-AWHF), was written off when it groundlooped on landing after a filming flight on May 21 . Wilson Connie Edwards, one of the American Confederate Air Force pilots working on the film, belly landed one of the two-seat Spitfires IXs, MJ772 (G-AVAV), at Little Staughton on July 9 after suffering engine failure during one of the filming sorties.

One of the taxying Spitfires collided with a camera crew at Duxford, thankfully without any major injuries to the crew or damage to the aircraft, during a take off scene, while at North Weald another of the 'taxiers', (XVI TE384), was tipped up onto its nose by actor Robert Shaw, who got a little over enthusiastic with the brakes during the middle of 'Weald's famous 'scramble'.

One of the film's 'few' was Squadron Leader Mike Vickers. Mike at that time was a QFI at RAF Valley and was coming to the end of his posting at the base. After having served in the Fleet Air Arm during the war, aboard HMS Formidable in the Pacific, Mike transferred to the RAF in 1949 and had flown many hours in piston-engined aircraft. He was just what the film's flying unit was looking for. After being selected, the then 44 year-old Mike reported to Duxford on April 24, 1968, to meet Wing Commander George Elliot, who was the 'flying boss' for the RAF side of the operation. I was the first of those selected to arrive, remembered Mike Vickers in 1999, so George Elliot made me his number two. That afternoon, George, who was the only really operational Spitfire pilot amongst us, checked me out on one of the film's two-seat Spitfires. I was subsequently given the task of checking out the rest of the pilots from the RAF as they arrived. We were initially based at RAF Debden, which was then the RAF Police Dog Training School, and we carried out most of the 'workup' flying, plus some of the early filming from there.

"If we're right, they'll give up. If we're wrong they'll be in London in a week" - Laurence Olivier

By the end of September the contract which allowed Spitfire Productions to operate out of Duxford was coming to an end, some of the RAF pilots were having to return to their parent units, leaving just a handful of service and civilian personnel on the flying unit. Work at Duxford was wrapped up and the unit moved to Bovingdon in an attempt to put the final sequences' in the can'. It was while operating out of Bovingdon that special clearance had to be obtained for the two Heinkels to fly up the River Thames estuary for the blitz scenes in the film. The last location filming took place at Netheravon, when Mike Vickers and some of the remaining pilots carried out some more dummy pilot parachute drops for the cameras. On October 22, almost six months to the day of my arrival at Duxford, the aerial unit ceased to operate, recalls Mike.  I had personally flown 110 hours in the Spitfires, 20 on the Messerschmitts and five on the Hurricanes. Those weeks had turned out to be one of the most interesting and exciting periods of my flying career.