When you started on Downton Abbey did you ever think it would become such a cult hit?

Absolutely not! No one sets out to make a rubbish series and we set out to do our best, but it took a while for us to realise it was gaining momentum and something approaching a phenomenon. After episode one, you expect the audience to drop off a bit but it went up. We had no idea it was going to make a splash. It’s lovely that it has.

Why did you take on the role of Earl of Grantham in Downton Abbey?

When I read the script, the characters were terrifically engaging. To make you interested in 16 to 18 characters, was remarkable. I really wanted to know what happened next. It was a real page-turner. It’s a testament to the quality of the writing that people wanted to be on board.

The character the Earl of Grantham has quite a moral compass…

Hardly! Like any human being, he is fallible and makes mistakes, but I’m very fond of him. He is a good dad, but his sole purpose is to ensure the security of the estate, so he has a pretty limited horizon. He can be witty and I love [the] relationships [he has] with his mum, and with Cora; Matthew who becomes the son he never had; and Bates and what they’ve been through. There¹s a good old bro-mance there! ‘He may be affable but he is no fool. He¹s not streetwise but he is wise enough to know human nature. I like that he is relatively shrewd but he’s a bit of a dinosaur otherwise.

Are there any parts of his character that you personally identify with?

I’m not at all like him, other than that I’m 6’2? and drop-dead-gorgeous.

What would be your career highlight to date?

I’ve been so lucky. I’ve enjoyed most of the things I have done, which is a bit of a wet answer. The most memorable was doing Notting Hill. I can remember every single day of that shoot, because it was the first big movie I had been on. I had such a laugh doing it because it was a great script and I was working with good people. I have the same sense of feeling with Downton Abbey. Working with great people with material we love: that comes through on the screen.

What do you like most about filming Downton Abbey?

My favourite memories are when we are all together. The group scenes, though they are a nightmare for hair and makeup, with 16 or 18 people together when we all collide and get together, it’s like a great family reunion and we love it.

What do you dislike the most?

The dinner scenes are a nightmare in terms of comfort, because of the stiff white shirts and razor blade collars. However, the array of costumes as we move through the seasons, from the Edwardian era, through to the 1920s in season three, is really exciting. Though, more so for the girls than the boys.

What advice would you give an actor or someone just starting out?

I was given quite a bit of acting advice by an agent, then I did the exact opposite and it worked okay. So the ultimate advice is to follow your own instincts. And don¹t think anyone else is going to make your career for you; you have to do it yourself. The phone isn’t going to ring necessarily. You have to find opportunities to show your talent, without being a pain in the neck. Like working in a box office or workshop of a theatre – you’re more likely to begin your journey like that than sitting waiting for the phone to ring.

What do you think are important attributes for any actor?

You need to have thick skin and thin skin. Thin skin is going to each audition and showing the vulnerability you may need to express in the role. Then you need to have thick skin when you walk out the door, which sounds [schizophrenic]. You must have an openness of spirit, and then the ability to shut down – otherwise, you go bonkers.

Have there been any tough moments in your career?

Yes, when I was at the Royal Shakespeare Company. I was hopeful of staying on for several years and it was indicated that I would, [but] a lot of my friends were kept on [and] I wasn’t. I was really knocked by that and thought I would never work again. Ultimately, I don’t know what the remedy was or how I got out of my blue funk. But you have to have quite steely determination and ultimately, a need. The industry is not for the faint-hearted. You spend a lot of time auditioning and largely the word “no” is involved. You need to be able to have confidence without arrogance in this profession, because it’s topsy-turvy. I was in drama school with people far more talented, who never had a break. It’s so much about luck. So once luck is allowed, you get an audition and in that audition you can show your talent.

What’s your next role?

Playing Mr Stink. It’s a charming and funny children’s story.