What was your biggest break?

If it hadn’t been for appearing on the BBC, my invention wouldn’t have made it to market. There were so many people who turned it down. But after I appeared on Tomorrow’s World, the phone didn’t stop ringing. A lot of those people who rejected the idea later came crawling back to me.

How important has it been to have a patent?

The truth is if I hadn’t taken out a patent, I would have been ripped off. No one pays you for an idea but they’ll pay you for a slip of paper that says you have an idea. It offered me protection in the early days from a large corporation suddenly saying, “Actually, we had that idea all along.”

How did you market yourself?

Doing TV and the radio appearances has never been a problem for me. Although, if I’d been paid as a publicity person for the product I’d be in a rather smarter house than I am now. But life isn’t really about money, and I’m lucky that I’ve been able to leave my mark with my inventions.

Do you approve of Dragons’ Den?

It’s just a game show. Yes people do come on with odd ideas, but we ought to respect anyone with the guts to stand up and have a go. Instead they are just laughed and sneered at. We should run the programme like a national treasure show, where all the inventors are respected and any one in the nation could phone in to invest.

What advice do you have for inventors?

If you have an idea, don’t tell everybody about it. People aren’t taught the basics about patents, so when they have a great idea they tell everyone and end up with nothing. This nation is built on brilliant ideas, but we are appalling at bringing them to market.