"Anyway, it is important for you all to realize that in a war like this, the enemy will do anything to any of you - civilian or soldier - if he thinks it will help him to win. Up here - and indeed for many miles around - is stored much of the water for the Midland cities. The Germans have tried to break our spirit by bombing and have failed, and this latest idea was particularly unpleasant as its purpose was to smash up the reservoirs and deprive of water those who work in the cities and towns and make munitions. There are several reservoirs in these hills, and the only way of destroying them is to blow them up. The only way to blow them up efficiently is to put the explosive in the right place, and to have it placed there by an expert. Bombing from the air couldn't possibly do this, so it must be done by what we call saboteurs - men or women whose particular job is to smash up or slow down the war effort. Thank God there are not many Englishmen who would stoop to such dirty work against their own country, and so such jobs as this must be organized by the spy who has definitely settled down and been accepted in this country and then carried out by men and women who are dropped in the dusk or at night from German aeroplanes. I expect you all realize that the Long Mynd is ideal for the landing of enemy troops. You youngsters, with the exception of Peter, have only seen a small part of the mountain, but it is wild and lonely for miles, and consequently very safe for parachute landings. It won't be so lonely in future, I might add, as we shall be watching it very carefully!

"Now what we think happened is this. Clever and unscrupulous spies were stationed in various parts of the country to organize plans for the destruction of water supplies. Mrs. Thurston was, of course, the agent in this district. She made herself at home amongst us and even if it took years to get herself known, liked and trusted, it would be worth while in the end. It was her job to send to Germany regular reports so that at a fixed time the Nazis could begin to send her carefully disguised assistants. Mr. Sterling will tell us, I've no doubt - and Peter, too, for that matter - that he has often seen her on the hills with field-glasses and camera, and that she has always been there for some purpose which seemed reasonable and unsuspicious."

Here Mr. Sterling looked at his plate in some embarrassment, and was heard to murmur something about bird-watching.

"Anyway," Mr. Ward continued, "we think that she must have personally examined and explored the reservoirs in this district to be destroyed, made maps, and then somehow got the messages to the Germans."