I was also a bit upset because I'd gone there – I wanted to do serious filming of animal behaviour, and I wanted to do some research too, on my chimpanzees. So what I did with these programmes was I cunningly slipped into them... each programme I did – and I did over 500 – each programme I did, I slipped in a few scientific facts, and I tried to do it in a way that nobody noticed because if I had started to become too educational, I'd have been in trouble; it had to be popular. But I was determined not to just show people, you know, the sea lions feeding or the elephants giving a walk or something. You know, I wanted – I had to do one whole programme sitting on the back of an elephant, I remember – but I tried to infiltrate into each programme a scientific concept.

I'll give you one example. I wanted to show that snake charming was a load of nonsense, because snakes are deaf. And when the snake charmer plays his flute like this, it's the movement of the flute back and forth that the snake follows. It can't hear anything so the flute-playing is a load of nonsense. So I thought, we'll demonstrate this. So we got a cobra. And, of course, unlike the snake charmer's cobra, this one was deadly because we... you know, we couldn't... I mean, what the snake charmer does is they either cut out its fangs or block its fangs or something. But we weren't... we weren't going to do that to a beautiful cobra. The cobra was intact and lethal; if it had struck, we'd have been dead within 30 minutes and a very painful death, too. So we were... we gave strict instructions to the camera crew not to make sudden movements or anything.

So there we were with live television with this basket with the cobra in it. And I said to Reg Lambourne, the reptile man... I said, isn't it going to slither out? And he said, no, no, I'm going to tape, very carefully – we won't hurt it – I'm going to tape its tail into the bottom of the basket so that it can rear up but it can't get out. So he did this and the lid was put on. And then we come to this item in the programme and I explain that I'm going to demonstrate to you now that snake charming is nonsense and that... because snakes are deaf. And we took the lid off. The cobra reared up and I played my flute like this and the snake danced and said... I said, now, you see, the snake is dancing to my music, isn't it? No, it's not! And I'll show you why this is nonsense. And then I played... I held the flute and I made the same movements but I didn't play it. And in complete silence, the snake, of course, made the same movements. So I was... I got my scientific point across. I taught two million people that snakes are deaf. And that was a scientific fact. And I made a nonsense out of this ridiculous snake charming act that everybody is so fond of. And that was fine.

But unfortunately we'd overlooked one thing. The snake was about to moult and as we watched in horror, it slithered out of its basket, leaving its skin neatly taped in the bottom of the basket – its shed skin – and slithered across towards camera number two. It's the only time I've ever seen a cameraman – television cameraman – operate his camera from above. He actually... in those days the cameras were big, not like today's little cameras – they were huge – and he climbed up his camera and was trying to operate it, sitting on top of it with a... with a deadly cobra at the base of the camera. And this was all, of course, on live television. I had to keep talking and I learnt to fly by the seat of my pants in those early days of television, and it stood me in good stead for later on. I did go on to make a lot of other television programmes, but that really wasn't my purpose at the zoo; my purpose at the zoo was to do research.

And I was lucky because I had a young chimpanzee that... he was a famous television star by now and I was able to spend three years, working on him with his drawings and paintings.