Pope Francis has said he made a vow 34 years ago to stop watching TV.

He revealed he slapped a ban on himself from watching television after stumbling across a smutty show.

The Supreme Pontiff said the vulgar viewing was so bad for his conscience that he hasn’t watched the box for almost 34 years.

He said: “I was watching television in the lounge with my fellow priests.

“It was July 15, 1990, and some scenes of an adult nature, to put it delicately, were being shown — something that was not good for the heart.

“Nothing risqué, of course, but when I went back to my room, I said to myself, ‘A priest cannot look at such things.’

“And so, the following day, during the mass for the feast of the Madonna del Carmelo, I vowed never to watch television again.”

His Holinesss, 87, said that one of the last things he watched properly on TV was the fall of the Berlin Wall - in 1989.

In his new book Life: My Story Through History, Pope Francis said there have been a couple of exceptions to his self-imposed sanction.

He added: “Only very occasionally do I allow myself to watch: for example, when a new president is sworn in, or I watched briefly once when there had been a plane crash.

“I switched it on, too, to follow Sunday mass while I was being treated at the Gemelli University Hospital in Rome.

“But I didn’t watch the coronation of Charles III, the new British king, for example, or many other important world events. Not out of disdain, but because I made a vow.”