HP/739
Confidential.
AIR RAIDS.
GROUND DEFENCES.

It must be remembered that our ground defences are planned to cover the defence of the whole of the United Kingdom and not one particular town or area. Scattered over the country are a large number of targets of military importance which we would like to protect by means of A.A. guns and balloon barrages. Our resources of guns are, however, strictly limited and therefore it is essential to use them for the protection of those places and areas whose safety is vital to our war effort. The priority with which such defences are allotted is the subject of constant consideration by the Chiefs of Staff of the three Services, and as new resources become available they are immediately deployed on a carefully prepared plan which is however revised as circumstances dictate.

With regard to balloon barrages, it is important to note that they are not intended to prevent bombing from a high altitude. Their sole aim is to prevent raiders flying sufficiently low over an important group of targets so as to bomb them with a greater degree of accuracy.

It must be remembered that searchlights cannot illuminate aircraft flying at a great height or when obscured by cloud. It is often useless for A.A. guns to open fire when their targets are not visible, but where a large number of guns are concentrated in one area, barrage fire against the unseen target has on occasions prevented accurate bombing. If our own fighter patrols are overhead the A.A. guns have to remain silent and, in fact, there are often serious disadvantages in bringing either searchlights or A.A. guns into action unless they have a reasonable prospect of success. Those responsible must be trusted to use their judgment as to when that condition is satisfied.

FIGHTER DEFENCES.

Our principal means of defence are the fighter squadrons which are deployed to cover the defence of the whole country and in particular those areas against which the strongest attack may be expected.

It is a common fallacy to suppose that because fighters are not visible from the town or area which is being bombed, therefore they are not on patrol. Our fighters are on the contrary sent up to intercept whenever enemy aircraft approach, but cannot be expected to be everywhere during the course of the 24 hours. Their aim is to intercept the enemy aircraft before they reach their objective. The speed of modern aircraft makes this essential and for this reason the fighter is frequently invisible from the place which it is protecting. For every hostile aircraft which is seen over London, Birmingham or Liverpool 305 2.there are a far greater number which have been effectively warded off or shot down in the course of their attack, many miles from these towns. In spite, however, of the efficiency of our fighter defence it must be realised that even during the day the enemy aircraft will always be able to break through and bomb, if they are willing to face the casualties entailed.

From experience it has been found that lone raiders, especially those using cloud cover, are often able to elude our fighters and that coastal towns are particularly liable to suffer from their attacks. Flying at 300 m.p.h. and taking less than 5 minutes to cross the Channel their approach must often be undetected and little or no warning can be given before they have dropped their bombs. Nevertheless, many successful interceptions over the sea by our fighters do take place, but of these, the inhabitants of coastal towns can know nothing. Moreover, it is not always possible to prevent raiders, which have been checked inland from splitting up and dropping their bombs on coast towns before they leave the country. When about to make large scale attacks against vital targets, the enemy occasionally details a few aircraft to bomb independently towns and villages on the flank of the main attacks and to act as decoys in order to draw off the defenders. On these occasions, protection of the vital target is uppermost in the minds of those responsible for our defence. This does not mean that lone raiders are allowed to attack unopposed, but it does mean that on occasions less attention can be paid to them than would otherwise be the case.

A suggestion frequently put forward is that small standing patrols of fighter aircraft should be provided for particular areas. Such patrols are in practice so wasteful and ineffective, that they are not even adopted to cover our most vital objectives.

It cannot be too strongly emphasised that at night, the interception of enemy aircraft by our fighters, even in good weather is extremely difficult, and in bad or cloudy weather is almost impossible. That the enemy are faced with the same difficulties regarding night interception is evident from their inability to shoot down our bombers on their long journeys over Germany and enemy occupied territory. Some of the aircraft heard at night are undoubtedly our own fighters in search of the enemy, but the fighter performing this task has not even the advantage of those on the ground of being able to hear the opposing aircraft. At the moment, even in the most favourable weather conditions, the percentage of night interceptions is comparatively small, but important scientific advances give promise that it will increase.

A common complaint is that London is better protected than the provinces. Observers of recent air raids over London will agree that if London received more than its fair share of the defences, which is not the case, these have been unable to prevent indiscriminate bombing. A reference to the map will show that towns in the south and south-east of England are nearer to the battle 306 3.front and consequently to the areas where the majority of fighter interceptions are made than those in the north. The latter are less likely to suffer from daylight raids since they are outside the range of the German fighter screen which accompanies the day bomber. Nearly all towns and areas in the United Kingdom are, however, exposed to the risk of attacks by night.

AIR RAID WARNINGS.

It should be realised that both by day and night, it is extremely difficult for those responsible for giving the warning always to guess correctly the ultimate objective of the enemy's forces and the limits of their probable penetration. Small forces of enemy aircraft sometimes break off at right angles from the direction of the main attack and inflict surprise attacks on targets which had, for the moment, appeared to be safe. The high speed of modern aircraft renders this form of attack peculiarly difficult to deal with and has on occasions caused the sirens to be sounded too late.

It should be noted however that warnings given after bombs have been dropped are not always in respect of the raid that has just occurred but are occasionally due to a heavy attack that is expected to follow. The numerous occasions on which warnings have been given and no raid has materialised are due to the fact that enemy aircraft have either been turned back or deflected from their course or for some other reason have been unable to press home their attack.

The warning system is continually under review in the light of experience gained. The difficulties of reconciling the claims of the public to receive adequate warning with the necessity of avoiding the inconvenience and dislocation which results from unnecessary warnings are, however, considerable. Consequently the public must on occasions expect to be bombed without being warned and be warned without being bombed.

ATTACKS ON GERMANY.

Since May 10th, the R.A.F. has carried out widespread raids on Germany. Their objectives have been of military importance and have included factories, power installations, oil refineries, docks, shipping and communications. For a number of reasons it does not pay us to adopt indiscriminate bombing for its own sake or as a measure of retaliation. The crippling of the enemy's industry and war machine is likely to lead to far more conclusive results in a shorter space of time. Some of the targets which we have attacked are, in fact, situated in thickly populated towns and districts, as indeed are similar targets in this country and, consequently the enemy civilian population has by no means gone unscathed. If our bombers fail to find their primary targets their instructions are to bomb secondary targets on their return journey. It is still true to say however that one of the best means of defence of the civil population in this country is the destruction of aircraft factories in Germany.