Books will soon need "trigger warnings" because some students do not like being faced with ugly truths, according to author Julian Barnes.

The Man Booker Prize winner made the suggestion after hearing that some undergraduates had taken to criticising Gustave Flaubert’s Madame Bovary on the basis of the protagonist’s behaviour.

Over the last two years, a growing number of UK universities have introduced "trigger warnings" to give students advance notice of potentially distressing material and "safe spaces" in which certain behaviours or language are prohibited. Both have been criticised by free speech advocates.

Speaking at a celebration of the Booker’s half-century on Sunday, Barnes told an auditorium at the Royal Festival Hall: "I sometimes get exercised by our stories being put up for examination on non-literary terms, and trigger warnings and all that stuff.”

He gave the example of US students who had criticised Flaubert’s masterpiece, who had said ‘I didn't like it because Madame Bovary is a bad mother".

The 72-year-old said: “I don't know where to begin to unpick that.

"As for students asking to hear in advance the bad things that happen in Titus Andronicus,” he said, to laughter, “we might as well have a trigger warning on all great works of literature.