The Second World War

The Second World War through primary sources.

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Written and submitted to this site by Eileen M. Younghusband

"Must be under twenty-one years of age, with quick reactions, good at figures and female". These were the prerequisites for members of the
WAAF seeking a commission as Officers working in the Filter Room. This Secret section of the R.A.F's Defence programme in World War Two has never
had the recognition it deserves. Nevertheless it was one of the greatest means of protection to Britain and aid to our air operations of the whole
war. The reason that very few people even today have ever heard about this is the extreme secrecy which the personnel maintained about its work
and its influences. Only recently have the restrictions been lifted and freed wartime members of this close group from the silence imposed upon them.
It is now time that the vital work of the airwomen plotters of the Filter Room and the WAAF Officer Filterers and Movement Liaison Officers in
charge of the calculating and identifying of the hundred of tracks of aircraft leaving and approaching the coasts of the British Isles should be

The Filter Room was the heart of the Radar system. It received information from the many Radar stations which formed a chain of protection
around our coasts. This information due to the early forms of detection equipment and possible human error of its operators needed to be instantly
corrected, co-ordinated and displayed on a huge table of the area concerned, in a form suitable to be passed on to the Operations Rooms.
It was this cleaned-up information that we have all seen in many films where WAAF airwomen move coloured counters of diverse shapes around a map
table, using a long pole-like contraption. From this information, orders were given by the Senior Officers sitting on the gallery above the table, for air raid warnings to be sounded in threatened areas, fighter squadrons to to be scrambled, incoming hostile aircraft be intercepted and returning bomber aircraft in difficulties monitored so air-sea rescue boats could be directed to their assistance, should they ditch. All vital tasks.

The country was divided into seven regions, including Northern Ireland and the Scottish Islands and there was a Filter Room for each. These were
manned for twenty-four hours daily from the commencement of hostilities until after peace was declared in Europe. Personnel were formed into four
watches. Sometimes it was impossible through illness or shortage of trained personnel to maintain this and a three watch basis was instituted.
This meant leave was impossible and other than eating, sleeping and working, there was little time left.

Personnel had two fifteen minute periods when possible during the watch for a refreshment break. The food available varied considerably.
Sandwiches of marmite and raw cabbage were offered at three in the morning for weeks on end at one particular station! Conditions of working were
often difficult and unpleasant. Many of the centres were underground where ventilation and heating left much to be desired. The pressure of
work depended upon the amount of aircraft activity and also the region covered. Naturally the northern areas were not as busy as the Filter
Rooms covering the coast from the Wash to the Isle of Wight and the Isle of Wight to Wales. The weather too was a key factor in the activity to be
expected so meteorological advices were posted constantly. The need for the Filterer Officers to have quick reactions was
patently obvious. They had to sort out the correct position of the aircraft from various Radar station plots which covered the same electronic
responses. They had to estimate both height and number of aircraft from information given, having intimate knowledge of the siting of the Radar
stations involved and judging their accuracy. All of this had to be done so swiftly as the aircraft themselves were constantly moving on to new
positions. It was found that male officers, mostly well over thirty years old were far too slow during periods of intense activity and they had to be
removed from the table!

For the displayed information to be of value to the Operations Room. it had to be as up-to-date as possible. This meant that in times of
greatest activity, a Filterer Officer must estimate and display salient information on up to fifty different tracks within a minute. The mental
stress and physical strain were intense under these conditions and when the personnel came off watch, whether officer or airwoman, tension was
invariably high. After coming off duty, throughout the following meal the atmosphere was almost hysterical as they gradually unwound. Quite often
sleep was impossible.

On the whole, it was amazing how few buckled under the strain. They all realised the importance of their work and it took a really major
illness to prevent them from appearing for duty. However, subsequently time has taken its toll of some amongst that small group. There have been
instances of suicide, of recourse to alcohol in later years and bouts of deep depression. This is not to be wondered at when one considers that
whilst filtering the tracks of the bomber squadrons on thousand bomber raids over Germany or plotting routine fighter sorties, these young women
knew that their own husbands or sweethearts were amongst the aircrews. They would count with trepidation the numbers of the returning aircraft.
The mixture of backgrounds amongst the members of the Filter Room officers was amazing. Most of the senior male officers hailed from the
Stock Market, jobbers and brokers. The women ranged from psychology students, young actresses, county debutantes, grammar school high flyers to
daughters of famous people - novelists, painters, musicians and vicars. Many friendships were forged under these conditions and remain close until

Now the strictures of secrecy have been lifted, it is surely right that their dedication should be recorded and the importance of their work in the
defence of Britain together with their contribution to the successful invasion of Europe and the ultimate overthrow of Hitler's forces made known.

This article was kindly submitted to the site by Eileen M. Younghusband in November 2004. Eileen retains all copyright of this text and it may not be reproduced without her consent.

Eileen Younghusband - lecroissette AT