Inspector Morse writer Colin Dexter has written a clause into his will to stop any other actors playing the TV detective.
Dexter, 83, told the Independent newspaper that he didn't want anyone trying to compete with John Thaw, who died in 2002.
"We never want to repeat what John has done," he said.
"A lot of people connected with Morse didn't want anyone coming to say we will try to outdo dear old John.
"I said I'm never going to allow that, full stop."