The Doc Martin actor joked that he has pestered friend and Downton creator Julian Fellowes for a part on several occasions.
"Julian is my neighbour. He lives just around the corner and I keep lobbying him but he won't," he is quoted as saying in The Sun.
"I might just ride into an episode out of spite.
"He knows where I am and what my measurements are, so it wouldn't be difficult."
Martin Clunes will star as mayor Len in the ITV drama The Town from tonight (December 5). He also revealed that he has pretended to be a real mayor in the past.
He said: "I have thought about running for mayor. I used to tell people I had been asked to be mayor and I even got into a row with a cab driver.
"He was trying to say there isn't a mayor and I said, 'There is now'. I was very proud and made my wife laugh when I became the mayor at last."
Andrew Scott, Julia McKenzie, Charlotte Riley and Kelly Adams also star in The Town, which begins its three-parter tonight at 9pm on ITV1.