The same could be said of RAF Fighter Command. The best had been given to 11 Group in south-east England but it was by no means ready for battle, while fighter squadrons elsewhere in Britain were, at this time, in chaos. At least one squadron was still flying old Hurricanes with fabric-covered wings. No. 73 Squadron had been the last to withdraw from France, where in a previous war its Sopwith Camels had flown. It had numbered 'Cobber' Kain, one of the RAF's first aces, in its ranks. But every one of its Hurricanes was undergoing repair, and there were only seven pilots fit to fly. No. 87 Squadron had only half its establishment of ground crews, and there were no armourers at all. Every squadron had shortages of some kind, and by the beginning of July, one third of the RAF's operational aircraft still had not been fitted with the IFF device that distinguished them, on the radar, from enemy blips.

Dowding — Fighter Command’s Commander in Chief — was deeply concerned with the task of bringing his squadrons to battle readiness, but he was keeping one eye on the calendar. His Air Ministry bosses had fixed 14 July as the day he must retire. Incredibly, the men of Whitehall had ignored all Dowding's enquiries about this forcible ending of his career, and it was not until 5 July that the Air Staff deigned to answer him. A smooth letter from the Chief of Air Staff said he would be very glad if Dowding could continue until the end of October.

Understandably irritated, Dowding replied: "Apart from the question of discourtesy, which I do not wish to stress, I must point out the lack of consideration involved in delaying a proposal of this nature until ten days before the date of my retirement. I have had four retiring dates given to me and now you are proposing a fifth…"

Dowding suggested that the Air Ministry stick to the first retiring date that had been proposed, which would retire him in two years' time, on his sixtieth birthday. In his reply Dowding listed the other retirement dates and short-notice changes. He added a petulant reminder about his brush with Churchill concerning the Hurricanes sent to France. "I am anxious to stay because I feel there is no one else who will fight as I do when proposals are made which would reduce the Defence Forces of the Country below the extreme danger point."

It was a rebuke to the Air Minister, and to the Chief of Air Staff, who should have been confronting the Cabinet with these dangers long before the personal intervention of Dowding himself. To emphasize the way he felt, Dowding sent a copy of the letter to the Air Minister as well as replying to the Chief of Air Staff. Dowding's reply was well justified but it did nothing to help his cause. His enemies were biding their time.

There were soft replies from the Air Minister and Chief of Air Staff, the latter smoothly remarking that he "was glad to have your support at the Cabinet when the question of sending fighter squadrons to France was under consideration." Having rewritten history to his own satisfaction, the Chief of Air Staff refused to give Dowding any assurance that he would be kept in the RAF beyond October. But Dowding felt reassured. At last he had given his grievance an airing, and compared with his previous treatment — rude letters, curt telephone calls, and ignored requests for information — smooth evasions were a decided improvement. For the time being, he seemed to have only the Luftwaffe fighting against him.

The supply of missiles rock, spear, or arrow had limited the duration of ancient battles, as had fatigue and darkness. Only when armies were supplied on the battlefield did the word 'battle' cease to mean a short clash of arms by daylight. By the twentieth century, the length of battle was unlimited. The Battle of Britain lasted not hours but months. I have divided the battle into four phases. Each is marked by a change in German tactics and targets but the four phases are not precise ones. The periods overlap, techniques were tried out side by side, and different types of target came under attack on the same day.

Phase one: Starting in July there was a month of attacks on British coastal convoys and air battles over the Channel: Kanalkampf.

Phase two: From 12 August the eve of Adlertag (Eagle Day) came the major assault. Göring and Nazi propaganda writers called it Adlerangriff (Eagle Attack). It continued for just over a week.

Phase three: What the RAF called 'the critical period', in which RAF fighter airfields in south-east England were priority objectives. This lasted from 24 August until 6 September.

Phase four: From 7 September. The attacks centred on London, first by daylight and then by night.

To begin, Oberst Johannes Fink, Gesehwaderkommodore of the bomber unit KG 2, was created the Kanalkampf-führer (commander of the air fighting over the Channel).

His task was to close the Channel to British shipping. To do it he was given command of two Stukagruppen and a Jagdgeschwader of fighters to add to his own bombers. Fink set up a command post on Cap Blanc Nez, five miles west of Calais, in a bus parked very near the statue of Louis Bleriot, first man to cross the Channel by air.

There was sound reasoning behind the German attacks against coastal shipping in July and early August. It had been decided that the Luftwaffe would launch its major offensive only after Hitler gave the order. It was presumed that the Supreme Commander was co-ordinating the plans of the army and navy: timing the air offensive so that the invading army would find the British defenders stunned into the sort of paralysis that the Luftwaffe had produced in France and Poland.

Meanwhile attacks against Channel convoys were a 'heads I win, tails you lose' proposition. If the RAF sent fighters to cover the shipping, they would be drawn into a battle of attrition and made tired before the Germans launched Adlerangriff. If RAF Fighter Command refused to be drawn, the bombers would sink the British ships.

Dowding had not calculated for shipping protection in his original plans, and now he warned the Air Staff, and the Admiralty too, that he could only protect shipping by committing a dangerously high proportion of his total force. So the convoys could have only minimal air support. Britain's radar network was not very effective during this Kanalkampf, for the fighters and bombers of the Air Fleets could climb to operating heights and get into formation out of 'sight' of the British radar. To cross the Channel took only five minutes but a Spitfire needed fifteen minutes to climb high enough to fight them.

As more and more ships were sunk, the pressure on Dowding increased and it is typical of certain members of the Air Staff at this time that they felt able to offer Dowding advice. They told him to put his fighters onto the coastal airfields, so that they need only take off when the Germans were close. To a limited extent this was being done, but it was very dangerous to be so near to enemy formations before gaining equal or better height, for the German airmen were formidable.

Kanalkampf-führer Fink was 50 years old and still flying operational bombing missions. The Kommodore of the fighter Geschwader assigned to him was also a veteran and an even more remarkable flyer.

Oberst Theo ('Onkel Theo') Osterkamp was a slim, fastidious man, with a large forehead and pointed features that made him 'gnome-like' to some. This impression was reinforced by anyone who had been on the receiving end of his quick mind, sharp tongue, or his machine guns. In the First World War Osterkamp had been an outstanding ace, credited with thirty-two kills and awarded the Pour le Merite. A close friend of von Richthofen, he had trained alongside Oswald Boelcke, had survived an air battle with Charles Guynemer, and been shot down by Albert Ball. He was one of the few such men to fly a fighter plane in the Second World War, and already the amazing 'Onkel Theo' was becoming an ace all over again.