Brian Cosgrove, co-creator, director, animator

We based Danger Mouse on a 1960s TV series, Danger Man with Patrick McGoohan, not James Bond as people always thought. We reckoned a secret service mouse foiling the plans of an evil toad – Baron Silas Greenback – was suitably ridiculous. We had trouble coming up with a sidekick. Mark Hall, my business partner in [animation studio] Cosgrove Hall, and I were waiting one day at Thames Television, our financial backers, for a meeting when I doodled this little fellow with heavy glasses and a baggy suit. Mark said: “That’s the one.” I’d actually drawn my brother, Denis. He was northern editor of the Sunday Express and was bald with heavy black glasses. He did start getting called Penfold in the office. I think he was rather pleased.

I was very lucky to find Brian Trueman as the main writer. At the time he was an on-air announcer at Granada Television. David Jason, who was the voice of Danger Mouse, had just started Only Fools and Horses and so was relatively unknown. His voice had the perfect mix of forcefulness, humour and gentleness. He was totally committed to doing voiceovers for silly cartoons, which warmed my heart, and we became great friends. Terry Scott, the voice of Penfold, had just done Terry and June and so was near the top of the tree. I got the impression he thought it was a bit beneath him, but he soon changed his mind.

I worked with a small group of animators. We had certain rules. Danger Mouse was a mouse living in a world of humans. When he drives around London, his car is mouse-sized – he could get stepped on! That’s what I like about animation: you can ignore common sense. We never talked down to our audience. Children were mature people, just small. We didn’t realise were making something that would achieve such a level of affection. It certainly wasn’t due to the quality of the animation, but I think Danger Mouse had heart. At one point in the early 80s our viewing figures – 21 million – were higher than Coronation Street’s.

We sold the show to the US in 1984 but did encounter one hiccup: Baron Greenback’s right-hand man is a crow called Stiletto who speaks with an Italian accent. The studio head there said: “You’re going to have to change the voice on that crow.” In the States they still had a big Italian community and the mafia in New York, and they said they wouldn’t accept a comical Italian accent. So we rerecorded Stiletto as a cockney. The show became so popular that they funded a co-production in 1988, Count Duckula, again voiced by David Jason, who we made a vegetarian vampire duck, which ticked us immensely.

David Jason, voice of Danger Mouse

I was doing voiceovers for all the commercials you could think of, and I’d just started Only Fools. It came through my agent that Cosgrove Hall were looking for someone to do some voices for a new cartoon series. I’ve loved cartoons since my mother took me to the cinema and they showed them between the presentations.

Facebook Twitter Pinterest ‘We were getting paid to enjoy ourselves’ … David Jason in the recording studio, with a Danger Mouse toy. Photograph: Fremantle Media/Rex/Shutterstock

I asked to see a picture of the character first – I wanted to make him sound believable. We decided he would be softly spoken, very British, very heroic, but also a bit of a coward. He’d save the world, but he’d also run for it! I tried to put all those elements into the voice. I think Terry, bless him, was a bit sceptical at first. He was a successful comic and quite a famous man who wasn’t used to working as a double act. We soon got on like a house on fire and he subjugated himself very much into the part. We always did a couple of takes, then Brian would say: “OK, let your hair down and do whatever you think.” I’d look up and see Brian through the glass, glasses off, falling around with laughter, handkerchief wiping his eyes. We were often told that the animators would ignore the script and work with what we’d done instead.

It wasn’t like work. We were getting paid to enjoy ourselves. It was extremely well written with great stories and no real violence, and a wonderful sense of old-fashioned Britishness. You don’t get much more simple-natured than Penfold and Danger Mouse, or DM as we called him. They’re innocent clowns, a bit like Laurel and Hardy.

We didn’t know Danger Mouse was so popular in the States. A couple of years ago I had to go to the American embassy to get a work visa. You know what it’s like: long queues, very official. When my turn at the little window came, the man said: “Is your name David Jason? Did you play Danger Mouse?” He almost fell over backwards. He said: “I grew up with Danger Mouse. It’s such an honour to meet you.” He then became the most helpful man in the whole of the country.

• Visit the Cosgrove Hall Films Archive at Waterside in Sale, Manchester.