ONE result of ‘the Downton effect’ is that the demand for British butlers has doubled in one year from the world’s wealthiest families wanting – and being able to afford – the kind of life they see in programmes like Downton Abbey.

Harrogate-born actor Jim Carter, who plays old style servant Carson the butler in ITV’s international television hit - which is filmed locally on location at Highclere Castle - isn’t about to give up acting for a life in service despite being offered jobs as a butler.

“People have approached me saying we’re getting married and love the programme so much we think it would be lovely if you came and were the butler for the day. We’d make sure you had a lovely time. And I think yes, or I could eat my left testicle,” he says.

Carter is someone who takes his work seriously and accepts the by-product – fame and public recognition - as something to be tolerated if not necessarily enjoyed.

Most fan mail is of the can-I-have-your-autograph variety although he says, “The rule of thumb is that if it’s on lined paper torn out of a notebook in green Biro, don’t bother reading too far down.”

Some perks are better than others. During a US press junket the cast were taken in a fleet of limousines to a late night visit to the White House which had been kept open especially for the Downton cast. “The president was away but Michelle Obama is a very big fan of the programme. Her housekeeper was there and she had cookies for us and drinks, and showed us around,” he says.

He finds a serious actor in the middle of a crazy circus. “Forgive me because this is going to sound twattish but I’ve been working for 45 years and you work for the work, you do it for the job, and the other stuff is sort of irrelevant. You don’t do it for that,” he explains.

“Then it comes along as an unsought for by-product of your work and you think hang on I’ve done the job, I’ve been paid, why do I need all that stuff? The red carpet hullaballoo or, forgive me, what we’re doing here at this press junket. That’s something in 45 years I’ve never come across really apart from a little bit through my wife (Imelda Staunton) when she was nominated for an Oscar. It’s not something we take particularly seriously because it’s not why we do it.

“Then it emerged that one of the unforeseen by-products of this was that we could translate this and elevate this spurious status into doing good works for charity. As a group we have raised millions for charity. Each year we do a big group charity event – this year I got one together for Special Olympics. Thirteen members of the cast turned up for that, people flew in from America to be part of it, we spread the word. And that’s a use I can see for all the flimflam.

“But otherwise the flimflam just gets in the way of your life. It’s all very nice but I find it very hard to know why me, why not that guy did his work on the camera because I can’t do my work if he doesn’t do his work. So I’ll go along there and sit in an air-conditioned barn with lots of famous people stuffed full of Botox and I won’t recognise half of them because they’re in programmes I don’t watch.

"And I’ll watch a young handsome American guy get an award, I’ll clap and then I’ll go off to a party where I can’t hear a word talking to people I don’t know.”

In the sixth – and final – series Carson, who proposed to housekeeper Mrs Hughes in the fifth series, has already found himself involved in delicate negotiations about what exactly he requires from the marriage – whether he wants, shall we say, a “full” marriage. It emerges that Carson is a bit of a softie underneath the gruff, you rang m’lud exterior.

“There are the odd moments when you get beneath Carson’s skin and find there is a little bit of a romantic heart beating under there. It’s nice to do that. The most interesting thing for me has been when you’ve seen behind the mask of Carson, the curmudgeonly stickler for tradition and get to see those moments of private moments. Those are the best things and they’re the most fun to play as well,” says Carter.

Carter isn’t about to spill the beans on how the series ends, other than to say that the final episode – to be shown on Christmas Day – wraps it all up nicely. “I read it and thought this is so going to work because it’s the audience saying goodbye to characters they’re fond of and not in a cataclysmic way. There are no great explosions or drowning or mass electricutions or anything. They’re just seeing them sort of disperse. It’s satisfying.”

Unusually for the filming of a TV series, the very last scene shot was the final scene in the series – a candlelit scene in the servants’ hall with the downstairs workers assembled. “I’s just a quiet gentle little scene and then at the end of it someone said ‘cut and that’s a wrap on the servants’. And you know we do a job, we move on to the next job. It happens all the time. So that was fine,” recalls Carter.

“Then some producers came in and said thank you everyone, it’s been great. And I felt I should say something and thanked the crew and looked up and there are the crew shattered, grey, knackered and I filled up completely. I started to go and big Lee, who’s one of the riggers, had tears pouring down his face, Bobby the grip and Duncan the sound guy were sobbing, Phyllis Logan (who plays Mrs Hughes) was a total mess.

“It really took me by surprise how affecting it was. People talk about we’re a family but we’re dysfunctional as well – a family with all that goes with it. The crew have been there throughout everything and have worked twice as hard as us. It was quite affecting to see their loyalty and them saying goodbye. It was very emotional. We knew it was a job and coming to an end, but on a visceral level it was very affecting.”

There’s been talk of a Downton movie but he thinks it’s “more wishful thinking than actuality” with no serious discussions among the cast about the idea.

Jim's already moving on to his next job – making a documentary on Lonnie Donegan, the king of skiffle.

“I’ve interviewed Paul McCartney already. He was lovely,” he says, and off he goes.

Downton Abbey is on ITV1 on Sunday evenings.