Professor Mary Beard has said she did not realise so many men dye their hair “but don’t talk” about their secret.

The renowned classicist and TV historian will present the significance of the hair-colour revolution in BBC Radio 4 documentary, Glad To Be Grey.

The academic will investigate when and why women started obsessing about turning grey and what this says about our attitudes to women and ageing.

Mary Beard in 2013Mary Beard in 2013 (John Stillwell/PA)

Talking to the Radio Times, the Shropshire-born star recalled the reaction of some TV views to her long, grey hair following BBC Two’s Meet The Romans With Mary Beard in 2012.

“I got tweets saying, ‘You look like a witch’.” She added: “And then of course dear old AA Gill drew attention to it.”

Writing for The Times, TV reviewer Gill had said: “Mary Beard should be kept away from cameras altogether.”

The 61-year-old responded to the criticism in an article, describing it as “poorly argued, carping sexism”.

“I was in America when I read it and you feel like you’ve been punched,” she said. “But actually, he did quite a lot of good because people really thought that what he said wasn’t on and that I looked perfectly fine.”

The respected figure started going grey in her early 30s, but decided against dyeing her hair. She is “glad to be grey”, but it is a view not held by many women.

“It goes back to well-mown issues where the white-haired craggy male talking about politics on telly is fine, whereas the wrinkled, white-haired lady isn’t,” Prof Beard stated.

“With men, the signals of ageing suggest authority, but with women they don’t.” A few women with a celebrity status do sport grey and silver hair such as US actress Jamie Lee Curtis or politician Shirley Williams.

But it is men who are celebrated and labelled as “silver foxes” when they finally stop trying to hide their true hair colour.

Top Gear host Matt LeBlancTop Gear host Matt LeBlanc (BBC)

In 2010, Friends star and new Top Gear presenter Matt LeBlanc admitted he had dyed his hair during the entire 10-year run of the popular US comedy.

This Morning’s Phillip Schofield has said he dyed his hair until the age of 40. Prof Beard was surprised by some of the revelations contained in the Glad To Be Grey documentary.

“I hadn’t realised quite how many men colour their hair but don’t talk about it,” she said.

Phillip Schofield Phillip Schofield (Dominic Lipinski/PA)

The respected writer may be an increasingly recognisable face on TV, with her CV containing programmes such as the BBC’s Question Time and a cameo in W1A, but her day job is as an academic.

“I can sit in the library with my grey hair until I’m 102 and no one will ever bat an eyelid,” she said.

BBC Radio 4′s Glad To Be Grey is broadcast on March 4