The British army is once again struggling to answer the question “What is the army for?” (first posed in 1905, by the then new war minister, Richard Haldane). The Royal Navy is equally unsure what it is for, save to operate Trident, the strategic nuclear deterrent.

But the Royal Air Force has its sacred and eternal mission: to defend the skies above Britain. It may, and does, do many other things – fly soldiers around the battlefield in big helicopters, fly soldiers to the battlefields in ever-bigger aircraft, kill the Queen’s enemies with air-launched missiles from fast jets or drones – but first and foremost it is the guardian of our towns and cities from aerial attack.

It is not just airmen and airwomen who know this, but (give or take the odd dullard) everyone in the country, not least because The Battle of Britain (1969) is a great film and shows up on one TV channel or another every September.

It is by no means certain that the Germans could have invaded in 1940 if the RAF had lost that battle, but the Luftwaffe’s failure to gain control of the air that summer meant that invasion was impossible. That was the import of Churchill’s encomium to Fighter Command: “Never in the field of human conflict has so much been owed by so many to so few.”

It was the issue of control of the skies above Britain that brought the RAF into existence in the first place. For most of the First World War, the Royal Flying Corps – a branch of the army – defended British airspace (with the Royal Naval Air Service primarily defending the naval ports), as well as taking the fight to the Germans in France, the Austrians in Northern Italy and the Turks in the Middle East.

However, in 1917, German airships – ‘Zeppelins’ as they were usually known – and, increasingly, four-engine “Gotha” bombers were beginning to inflict significant casualties on the home front, and the RFC appeared to be no match for them. On 13 June, 162 civilians were killed and 400 injured, including many children, in a daylight raid on London by 15 Gothas. Over 72 tons of bombs fell within a one-mile radius of Liverpool Street Station, while more fell at Fenchurch Street and in the East End. RFC and RNAS aircraft had been barely able to get within striking distance of the bombers.

Further reading

Has Germany forgotten the debt it owes Britain?

By Allan Mallinson

When the Gothas returned on 7 July, the defenders made better contact, but only one was destroyed and the casualty list was still high at 57 killed and 193 injured. The Daily Mail thundered that Britain had not been “so humiliated since the Dutch Fleet sailed up the Thames in 1667” and called for the heads of those responsible.

David Lloyd George, then prime minister, decided he had to act. In June, he had co-opted the former Boer leader General Jan Smuts to the war cabinet, and now he asked him to carry out a study into the air defence of Britain, the air organisation generally, and the arrangements for the higher direction of aerial operations. Smuts agreed at once. Within a month (on 17 August), he had submitted his report to the war cabinet, recommending:

We must create the new directing organization – the new Ministry and Air Staff which could properly handle this new instrument of offence, and equip it with the best brains at our disposal for the purpose. The task of planning the new Air Service organization [amalgamating the RFC and RNAS] and thinking out and preparing for schemes of aerial operations next summer must tax our Air experts to the utmost.

The report met with a mixed response. The RFC and RNAS did not want to lose the connection with their respective services. Lloyd George began to have second thoughts, and, his spirits low with the news from France of the faltering Passchendaele offensive, went on holiday in early September. The press, not knowing of the actual Smuts report but hearing rumours of dissension in government and among senior officers, again began pressing for action, not least when the Germans mounted heavy attacks on London and the east coast over four successive nights at the end of September.

A fortnight later, the War Cabinet received a paper showing that German aircraft production was increasing alarmingly, and on 15 October, during continued questions in Parliament, Andrew Bonar Law, Leader of the House of Commons, sensing serious disquiet, hinted at the formation of a separate service. It was confirmed in an official announcement the following day, and much to Lloyd George’s relief, in November the Air Force Bill passed through Parliament with little opposition. Nevertheless, most senior army and navy commanders thought it a grave mistake. When the Royal Air Force came formally into being on 1 April 1918, wags said the initials “RAF” stood for “Royal April Foolers”.

There are still theoreticians – and some practitioners even – who believe that the existence of a separate service promotes the fallacy that airpower alone can win wars. They point, for example, to the huge opportunity costs of Bomber Command during the Second World War, whose head, Air Chief Marshal “Bomber” Harris, insisted that strategic bombing unaided could bring Germany to its knees.

Further reading

Can Britain's armed forces survive their retreating budgets?

By Allan Mallinson

They point also to the fact that the US Air Force was formed only after the war. They also argue that, since all campaigns are integrated, multi-agency affairs, there is no reason why one aspect of a campaign – air control – should merit a discrete service.

But this is to ignore history and human nature. Only the existence of a separate service, focused solely – selfishly indeed – on its essential purpose will keep the necessary edge in equipment and techniques. This is why the Royal Air Force was brought into being a hundred years ago, and why it will undoubtedly celebrate its bicentenary.

Whether, though, a hundred years from now those magnificent men [and women] in their flying machines will actually be in their flying machines or piloting them remotely – perhaps even telepathically – is another matter.