David Attenborough has said he will finally stop making nature documentaries when he can no longer climb the stairs.

The 91-year-old broadcaster who has been making programmes for 75 years, once claimed he would never retire from filming.

But speaking to the Radio Times, he admitted that when he can no longer meet the physical demands of directors, he will stand down.

In his latest film, Attenborough and the Sea Dragon, which explores the a new species of ichthyosaur found in the fossil beds of Dorset’s Jurassic Coast, he was asked to repeatedly walk up a tall spiral staircase.

“I did it at least six times because of these bloody directors,” he said. “‘Could you turn a little sooner? Could you look over here? Could you walk down the steps, as well as up?’

“If I can’t walk up and down steps any more, that will stop me. Yes, I do dread not working, although there are things I can do without running up steps six times – books to be written, things I’ve never got round to. But at the moment it seems to be all right.”