The Berlin Wall limited my opportunities. It quite literally stood in my way. However, there was one thing which this wall couldn't do through all those years: It couldn't impose limits on my inner thoughts, my personality, my imagination, my dreams and desires.

I didn’t fear failure. I expected failure. I think I’ve always been somebody, since the deaths of my father and brother, who was afraid to hope. So, I was more prepared for failure and for rejection than success. The success took me by surprise and it frightened me.

At first the research did not seem to be particularly interesting – I carried out a systematic search for processes that might destroy the CFCs in the lower atmosphere, but nothing appeared to affect them. We knew, however, that they would eventually drift to sufficiently high altitudes to be destroyed by solar radiation. The question was not only what destroys them, but more importantly, what the consequences are.

No. I mean if you fail 70 percent of the time, you had a great year. You're dealing with failure seven out of ten times as a hitter.

From one particular piece of the sky an unclassifiable signal sometimes recurred and my brain started to say: “You’ve seen something like this before, haven’t you? You’ve seen something like this before from this bit of the sky , haven’t you?” I got out previous recordings from that bit of sky. It often wasn’t there, but when it was, it was keeping its place amongst the stars.

Occasionally there would be something I didn’t recognise and I’d record it with a question mark or, as a joke, LGM for Little Green Men. It was easier than saying “you know that funny pulsing source at right ascension 1919, declination plus 20”. So, it became LGM.

I was very, very thorough, making sure I really understood how that telescope worked, and that it was working properly. I was quite convinced that I wasn't clever enough to be in Cambridge and would be thrown out at some stage. My policy was to work as hard as I could so that I'd know I'd done my best. We now label this as impostor syndrome, but we didn't recognise, and certainly didn't name it, back then.

Yes, in 2018, I was awarded the Breakthrough Prize for the discovery. I was a bit dumbstruck, never expecting that kind of thing to happen. I was keen that the money should be used well and the best way to do that seemed to be to encourage a more diverse research student population from under-represented groups.

Tony was cautious. He suspected I’d wired the radio telescope up wrong. So we checked on another radio telescope on the site. The thing was pulsing nicely on mine but as we stood by the pen recorder of this other telescope, nothing happened. It was a horrible moment. And suddenly there it was, five minutes later because we had miscalculated when the telescope would see it. If we’d miscalculated by 25 minutes, we’d have all gone home and the story would be different.

It looked like an agricultural frame, something you might grow peas up – a lot of wires and cables strung from posts over a space the size of 57 tennis courts. It was actually built to study radio emission from quasars. I built the prototype and then six of us took two years to build the real thing.