Martin Freeman has said that he doesn't want to film longer runs of Sherlock, despite the wish of the show's millions of fans that more episodes were made per series.

The actor, who plays John Watson opposite the Benedict Cumberbatch's Sherlock Holmes in the drama, said that even if the BBC decided to make a longer-running series of the smash hit show, he would begin to get bored.

“People say make more," Freeman said in an interview with Mark Lawson at the Edinburgh Television Festival. "It’s like with The Office and it’s 'OK, yeah, but in five years you would hate us'.

“I’m not in charge of the show. But I am kind of glad we don’t do it all of the time because I have a very low boredom threshold. I really do. I want to do other things. What starts off as a real pleasure and feels like playtime would feel like 'Oh God' for me.

“I didn’t go into this world as a replacement for a proper job. I like the unknown. I like not knowing what I am doing next. I think this is an adventure. I am like, I am not working for six weeks let’s try and get something on. If it were nine months of [filming] Sherlock, the first month would be great and the next eight would be 'Oh, Christ…really?'”

Freeman did have a spell on the set of Sherlock earlier this year to film a special set in the Victorian era, expected to air around Christmas or early next year. A new series will also begin filming in 2016.

During his spare time he said he had been to see his co-star Cumberbatch's Hamlet at London's Barbican Theatre and praised his performance.

"He was really good, he was very clear, he made Shakespeare very accessible with his mouth,” he said, adding that he did not give his friend any advice because it wouldn't have been “helpful".

“When someone is doing a play you can only be positive. Nothing else is helpful because they can’t do anything about it.”

Freeman, who recorded a Labour party political broadcast during the last election, also revealed that he was a supporter of Jeremy Corbyn in the party’s leadership election.

"I happen to think he is the most impressive one of the four [candidates],” said Freeman.

“I respect all of them because I wouldn’t do it and they are all on my team but he is the most impressive as an individual."

Despite his political affiliations, Freeman said he has no interest in launching a career in politics and revealed that he turned down an invitation to appear on BBC panel show Question Time after his public support of Labour earlier this year.

Don't miss the Women of Sherlock – Amanda Abbington, Louise Brealey and Una Stubbs – speaking at the Radio Times Festival. Book your tickets here...