Margaret Thatcher has topped a Women’s Hour list of the most influential women of the past 70 years, a choice that even the judges admit was the source of “enormous contention”.

One panel member, Ayesha Hazarika, a former adviser to the Labour MP Harriet Harman, said she felt “uncomfortable” with the choice of Thatcher, but said the list was about celebrating impact “both positive and negative”.

For the past two years, Women’s Hour has compiled a list celebrating the global impact of women on other women. But this year, to mark the BBC Radio 4 programme’s 70th anniversary, the remit of the list was expanded to cover female achievement over the past seven decades.

The panel was made up of seven women, including businesswoman Karren Brady, screenwriter Abi Morgan, former Women’s Hour editor Jill Burridge, and Julia Hobsbawm, the founder of Editorial Intelligence. It was chaired by the journalist Emma Barnett.

Speaking about the decision to put Thatcher, the UK prime minister from 1979 to 1990, in the top spot, Barnett said that, no matter what your view of her politics, “she redefined power”. “Thatcher was one of the most iconic leaders of the 20th century, regardless of gender,” she said. “These are all things you can’t deny. She shaped how women viewed what it was to be a woman in power, from the way people articulated themselves to the way people dressed.

“She shattered the glass ceiling into tiny splinters and just by having a woman in power, little girls knew they could do it – even if it’s not the power you would have wanted.”

Barnett stressed that impact did not always have a positive meaning and pointed out that even for those who viscerally dislike the late Conservative politician, she politically galvanised a new generation of women in opposition to her.

Facebook Twitter Pinterest Bridget Jones, as played by Renée Zellweger in the 2001 film of Helen Fielding’s books. Photograph: Ronald Grant Archive

“It would be easy to put seven really worthy women who make you feel warm and gooey inside on this list, but that isn’t what impact means,” said Barnett. “Thatcher spawned a whole other generation of feminists in complete opposition to her and so in some ways her impact was to provoke huge change from the left and beyond.”

Hazarika said that she had “lost the argument about Thatcher” but conceded: “Whether you loved her or loathed her, hers was a very significant achievement. Thatcher shaped a generation and shaped a period in British history.

“I think she had a massively negative impact on society and on women but she was important because she showed that just because you [have] a woman in Downing Street does not mean you have a feminist prime minister or a feminist government.”

The list of seven spans a broad spectrum of women, dead and alive. And not all are household names. Second on the list is Helen Brooks, who set up contraceptive services for women in the UK and – in the words of Barnett – “gave women the key to controlling their own bodies”.

“She changed the lives of unmarried single women. When I went to get the pill for the first time, I didn’t know Helen Brooks’ name and I feel like I should have,” added Barnett.

Also included is the former Labour MP Barbara Castle, who brought in the Equal Pay Act, polarising feminist Germaine Greer, and the performer Beyoncé. Perhaps the most unexpected name on the list is Bridget Jones, Helen Fielding’s hapless fictional character, who burst on to the scene in 1996. The decision to feature Jones caused such disagreement among the panel that Hazarika joked that they almost called the supreme court to arbitrate.

Barnett said that even though Bridget Jones was fictional, she had had an undeniable and valuable impact on the way women were perceived, and could publicly express themselves, over the past two decades.

“Bridget is Marmite on this list, and believe me, it was not an easy discussion – the judges were completely split,” said Barnett. “It’s very easy to pack a list like this with people you should, and people you ought, to have there, but I think we forget that Bridget Jones is our Sex and the City. She’s our flawed heroine, that character which enabled women who didn’t have children, didn’t have the perfect life, to laugh at themselves and feel unashamed of who they are.”

Hazarika was also among those who had voted in favour of the character. “We wanted the good, the worthy, the brave, the liberating, the fierce – but we also wanted a bit of the fun on our list,” she said.

Hazarika said the blow of Thatcher topping the list had been softened by the inclusion of her wildcard suggestion, Jayaben Desai, the prominent 1976 Grunwick strike leader who campaigned against low pay and poor conditions.

“Jayaben was this tiny 4ft 8in woman in a sari who had dockers and postal workers from across the land coming to support her on the picket line,” said Hazarika. “She made trade unions realise solidarity was not just for white working-class men, but spanned right across immigrants and women as well. So it was great to be able to shine a bit of light on her and her story.”