There was a great shortage then of people who were able to both understand the technology that was going on, which was that equipment was being developed enormously fast and it was being introduced immediately into… into the RAF. And you needed people who were… knew all about the equipment, how it worked on the bench and thoroughly understood it, and who could go with it when it was being installed in the squadrons and teach them actually how to use it and what it was for. And that's where I first met Martin Ryle because he was involved with radar countermeasures, jamming the German radars, both on the ground and… and in the air. And I got involved there with a device which was jamming airborne interception radar, the thing that you would fit in ME110s or something like that, and this was a device which simply poured out radio interference from the tail end, actually, of a Flying Fortress bomber and blinded the radars of the… of the interception fighters. Most of our bombing was done by… at night then so that you needed radar to… to catch your target if… if you were a German night fighter pilot, and the idea was that this equipment would radiate noise at high level and just blanket the screens of… of the German night fighters. And so I went out with this… with this device which, as I said, was mounted. They had particular aircraft which were full of antiradar equipment of one sort and another, both jamming the ground radars and also the airborne ones. And I got involved with this particular one which had antennas mounted in the tail of a Flying Fortress. And the idea was to fly these fortresses in the bomber stream and, as I said, blanket radars of night fighters coming in to intercept. So I had, first of all, to know how the thing worked and I spent some time where it was being fabricated at… General Electric Company, GEC, Wembley. I… I was there when it was actually finally made and built and then I went out to the squadrons which was in Norfolk and oversaw the installation of it and taught them actually how to twiddle the knobs, and… and use it. And that was both instructive, from the point of view of physics – I mean, I learnt all about electronics and a couple of circuits and transmitters and all that kind of thing, but I also learnt hands on physics and… and what you do to make these things really… really operate. You had… I wangled flying with it, not on active service because I… I was a civilian scientist and you weren't allowed to do that, but I flew quite a lot over Norfolk getting the thing tuned up. If you're too close to the ground the antennas get interference from the ground reflection, so you had to fly it to get it tuned up nicely. And so I spent time flying over Norfolk doing… doing that, which could be quite exciting, actually, because the pilots would practice manoeuvres and things and I… this equipment was mounted, as I said, in the tail, but the controls were in the middle of the aircraft, and these were Flying Fortresses which have a big observation turret right in the middle. And I once saw the ground out of the turret and thought, my God, this is a Fortress and we're nearly upside down! And when I questioned the pilot afterwards about this, he said, you know… I said, ‘Do you normally do this sort of thing?’ And he said, ‘Oh, just practising countermeasures in flying.’ I mean, you… you have to escape sometimes and you do all sorts of things in aircraft, so the fact that you could throw these four-engined bombers around like that was quite… quite a surprise to me. But at any rate, I mean, the war taught me about physics, electronics and about people and, as far as I was concerned, it focused me in the sense that I wasn't focused when I went straight up from school, so I always recommend students now to have gap years if they can, especially if they're a little bit backward like I was, in a sense. I mean, I… I wasn't a good student in my first year; I spent time rowing but when I got back in 3 years’ time I didn't. And I was much more serious and I got a good result finally, but it was the war that, I think, did that.