One or two other things to say about the H2S equipment particularly. We gradually improved it. My staff began to be increased. There had been an independent development going on for Coastal Command radar. Well, that was cancelled and that group was put under my control, so I had achieved now... my own group was now quite large and it had a lot of very good people in it, and the H2S equipment was as a result got steadily improved. We were constantly putting in modifications, which very quickly got onto the production line and more and more bomber force were carrying this equipment. But nevertheless we were constantly attacked by our own people in the research department that our equipment was dangerous because the Germans would be able to home in on it and all that sort of thing. Well, my chief contact in Bomber Command was Group Captain Dudley Saward who became a great friend, and Saward. I would go to see him or he would come to see me almost every day, and one day in the early autumn of 1943, he took me out to dinner in Malvern, I remember, and he said, 'Do you mind if we walk back over the Worcester beacon' and I thought there was something on his mind, and he said that, 'I'm sorry to have to tell you that we had extremely heavy losses last night. The evidence is now perfectly clear that the Germans are homing onto your equipment', and I said, 'Well, how are they doing that, Dudley?' And he said, 'Well, they're attacking from the stern and below. Do you know we were around the top of the Worcester beacon?', and I said... suddenly I looked across and I said, 'Dudley, am I correct in thinking there is no high ground between here and the Urals?', and he said, 'I think that is so'. And I said, 'Well, look here, could you send me a Lancaster Bomber tomorrow and I will do something'.

So the next day a Lancaster Bomber arose. The answer was very easy. We would give the rear gunner a separate display of the cathode ray tube screen, in which the central region was expanded, so that whereas the navigator was seeing the whole area in front of them, the rear gunner would just see the aerial sky beneath him, right to the ground in which an aircraft could be seen approaching and I sent... a photograph of that is now in my archives in the Imperial War Museum. We fitted it in this plane, which Saward had sent and we arranged for a Mosquito to make an attack, a spoof attack on our aircraft and the result was marvellous. You know, there was the attacking aircraft coming at the spot of light. You could see him slowly approaching our rear gunner. Well, of course, it became... when this was put into manufacture and use with astonishing speed. It only meant for the manufacture one new cathode ray tube unit and a length of cable. This enabled our rear gunners to deal with the attacking German fighters.

The other thing at that time, shortly either before or after that event, Saward came into my office and said, 'I'm afraid that we're not doing very well on Berlin. Your H2S equipment doesn't show up much detail there'. Now, I had a big map on my office wall of the whole of Europe and I looked at Berlin and saw that below Berlin there were two very big lakes, the Wannsee and another name. And I said to Dud... I said, 'Look, we have a 3 cm equipment that is with a third of the beam width on test. If you could arrange to send six Lancaster's to Defford, we'll fit them with this new 3 cm equipment'.

Now, that happened and in the November of 1943 it was first used to lead the path finder force and the cover of my book, which I wrote very, very much later Echoes of War, the dust cover of that book has a photograph of the cathode ray tube as the bomber was approaching Leipzig and it shows the clear town of Leipzig and the railway station, with the bombing circle, so Leipzig was devastated that night and a few nights later it was used over Berlin, so the story went on like that. I must say, you know, it was total war in those days, but in later life I've being... what shall we say? Consoled by the fact that the equipment for which I was made to develop was used so effectively against U-boats as well as destroying and killing so many Germans.