It is the softly spoken radio show that provides good-natured help and advice to thousands of gardeners every week.

So regular listeners to Gardeners’ Question Time may be horrified to discover it has been accused of peddling racial stereotypes.

According to an academic, the sedate Radio 4 panel show is riddled with "racial meanings" disguised as horticultural advice.

One current presenter, Bob Flowerdew, rubbished the idea, calling it “ridiculous”, and asked whether experts on the show “should stop using Latin names to avoid offending the Romans”.

But Dr Ben Pitcher, a senior lecturer in sociology at the University of Westminster, claimed the programme’s regular discussions on soil purity and non-native species promoted nationalist and fascist beliefs.

Speaking on another Radio 4 programme, Thinking Allowed, the academic said: “Gardeners’ Question Time is not the most controversial show on Radio 4, and yet it is layered with, saturated with, racial meanings.

“The context here is the rise of nationalism. The rise of racist and fascist parties across Europe. Nationalism is about shoring up a fantasy of national integrity. My question is, what feeds nationalism? What makes nationalism powerful?”

Dr Pitcher said the “crisis in white identity in multicultural Britain” meant people felt unable to express their views for fear of being called racist, so expressed their racial identity in other ways, such as talking about gardening.

Speaking on the same programme, Lola Young, a crossbench peer and former professor of cultural studies, backed Dr Pitcher’s analysis.

She added: “I remember back in the late 80s-early 90s when rhododendrons were seen as this huge problem, and people were talking about going out rhododendron-bashing.

“That was at a time when P***-bashing was something that was all too prevalent on our streets.”

However Mr Flowerdew, a regular panellist on the show, denied that people who enjoyed talking about gardening were closet racists.

He said: “People aren’t gardening because they have some narrow nationalist view of the world.

“They are gardening because they enjoy it and they like to be outside in nice surroundings.”

He added: “We’ve been out in our gardens for more than 150 years so I don’t quite see how that fits. I think it’s ridiculous.

“Does he want us to stop using words altogether? Perhaps we shouldn’t use Latin names to avoid offending the Romans.

“The real problem is that language can be used and abused by anyone who wants to do mischief.”

A BBC spokesman said: “The passing mention of Gardeners’ Question Time was part of a broader discussion about language and race... the comment simply reflected the programme’s use of accepted gardening and horticultural terminology.”