Dame Joanna Lumley was confronted by disgruntled farmers after giving a speech calling the meat and dairy industries the “greatest source of animal cruelty on the planet”.

The vegetarian actress and campaigner delivered a lecture to a packed theatre in Oxford, telling the audience that she was increasingly turning to a vegan diet, and calling for the public to eat less animal products.

Dame Joanna’s views were called out by farmers at the Oxford Literary Festival event, as members of the audience urged her not to “mark farmers as bad people”.

The actress responded by saying she meant no “insult” with her lecture, in which she stated: “Farming animals is the greatest source of animal cruelty on the planet.

“The magnitude of it, you can’t even imagine it – 80 billion of them are slaughtered every year.”

In her talk on behalf of the charity Compassion in World Farming, of which she is a patron, Dame Joanna said the organisation was urging people: “Eat less diary, eat less meat, it’s bad for you, it’s bad for the animals, and it’s bad for the planet.”

At the end of the actress’s address, a female member of the audience rose to declare that she was from a farming family and took issue with Dame Joanna’s speech.

‘Please don’t mark farmers as all bad people’

The woman told the star: “Could I just speak up on behalf of a farming family Warwickshire who farms so beautifully. That’s my experience of over 70 years of being in farming.

“Everybody I know farms with compassion. Please don’t mark farmers as all bad people because they are not. Without farms it is very, very sad world.”

Lumley diplomatically explained that her comments were about factory farming in particular, saying that she hoped her speech was not “insulting to fine farmers”, but was then addressed by another woman in the audience who said she was from a “farming family too”.

She complained to the Absolutely Fabulous star that the audience had “heard so much negative stuff today”, adding: “Where you all want to walk, and enjoy, is farmland.”

Dame Joanna said her speech was too short to address all farming issues in-depth.