I'm sure dad would be absolutely delighted that I was taking over his role and having fun with it, because he took the business seriously but he wanted to have fun and he wanted to enjoy what he was doing. And my goodness me, he did. He really put a lot into everything. What I didn't want was, you know, 'Patrick Troughton’s son is doing it because he's the son'. I want it to be a bit of me, as well as dad mixed in. I said right from the start, I'm not Jon Culshaw, I cannot do brilliant impressions of voices and people, but what I can do is act the character.

It's a sort of mixture of myself and Patrick and to be honest, because I'm his son, it gets quite close I think. The real problem with trying to recreate dad on audio is that he was such a physical actor. It would be looks, it would be movements, it would be various things. So I've had to grab certain mannerisms he has.

For instance, he used to cough. And everybody used to think that was part of his performance, but actually it was a cough to give him time to remember the next line. And so I put a bit of that in.