The actor, who joined the soap in 1982 as Alan Turner, told the Radio Times that he had never left as he did not believe he was good enough to land another job.
"I ought to have regrets about staying, but I'm the laziest human being alive so I don't," he said. "The advice I've given to young actors has been not to stay too long. I told one actor he was too good to stay, and happily he left and has gone on to forge a good career. There was no point in me moving on because I wasn't good enough!"
The 78-year-old bemoaned Turner's lack of recent storylines.
"I would hate to leave, but I wish they'd find more for me to do," he said. "Recently I went to a cast meeting and a lot of people there had no idea who I was. Perhaps they thought I'd stumbled in off the street."
He added: "I suggested Turner get a love interest but the writers said they'd have to dig her up. I'm too old for bonking and too posh to be a Dingle."
> Thorp blasts new Emmerdale cast plots