The Halifax containing the equipment was moved from Hurn and landed at Defford satisfactorily, and we continued to use our tests there. I had then assembled a group of about 15 people, I suppose, of various types, and I ought to say about the code name that was given. My original files on this subject were named called BN, for Blind Navigation, and when Cherwell saw this, he went into a rage and he said, 'Look, you're not designing a navigation equipment, you're designing a bombing equipment', and he said, 'We'll call it H2S because it stinks', because it ought to have been done a long time ago and therefore it became known as H2S, and that was the official code name of this equipment.

We had even in this crude elementary state, the government had placed an order for 200 crash equipment as we called them. Crash programmes, 200 equipments with the firm of EMI and the other problem was that the system was not allowed to use a magnetron because it was so secret. We were to use a klystron which could be destroyed anyhow and those principles are well-known. So EMI were given the problem of making a klystron equipment with enough power to do what we were doing with the magnetron. And so in early June, when we... we had been making slight improvements and I remember flying with it over the Bristol Channel and it was particularly good on coastlines and the coastline and an airport between Gloucester and Cheltenham. I've got a photograph of it, it was on the cathode ray tube. Gloucester and Cheltenham showed up as big blobs on the tube, and so did the airport. So we thought, on Sunday, we'd had a weekend conference with these EMI people, including Blumlein at Defford, and we had flown the equipment on the Saturday night and it looked quite good. And the next day, the Sunday Blumlein said, could he and his team go up and see how the system was working.

So O'Kane and Hensby were both in my group and O'Kane and I had been up the night before, so we asked Hensby to take up these EMI people and the Halifax took off at about 2.00 o'clock and I retired to Malvern and the aircraft never came back. O'Kane remained in Defford and after a bit he phoned me and he said, 'There's trouble. The aircraft has not returned'. It, in fact, had crashed in the Wye Valley and it killed everybody on board, and that night I was grasped by the group captain who was in charge at Defford Station and he drove O'Kane and me to this remote place in the Wye Valley. Look, I was still a youngster in my twenties and it's just unforgettable. There was the burnt out remains of this bomber and we searched the wreckage and the only thing we could find which we could recognise was this cavity magnetron. We knew it could not be blown up anyhow. Well, I thought that was the end of H2S. I thought it was hopeless. We'd lost our only equipment. The thing was simply not working very well anyhow. No, that was not the case.