Miriam O’Reilly has blamed “deep-rooted misogyny in newsrooms” for the way male presenters are nearly always seated in the position considered more senior on the left.

The former Countryfile host was speaking after BBC Breakfast came under attack for placing a younger, less experienced man on the left-hand side of Louise Minchin on the BBC Breakfast red sofa. The left-hand slot, previously filled by veteran presenter Bill Turnbull, is typically known as “presenter one” by TV producers and is often filled by the most senior member of a presenting duo.

O’Reilly, who won an ageism case against the BBC after being dropped from Countryfile, said: “It’s just deep-rooted misogyny in newsrooms where editors think a man somehow has more authority ... And of course the people who make these decisions tend to be men themselves.”

“I’ve worked on enough news and current affairs programmes to know that men are seen by editors as having the ‘gravitas’ to lead a show. Sadly women on breakfast news programmes, particularly, have the role of the bit of fluff by his side. They are there to smile, laugh, giggle or tease – and to show legs and cleavage.

Former Countryfile presenter Miriam O’Reilly. Photograph: Graham Turner/The Guardian

“These women are accomplished journalists who could lead the shows on their own with credibility.”

However, Julie Etchingham, the award-winning presenter of ITV’s News at Ten, said she was less worried about where her male co-host sat than whether or not she was getting equal billing. “My bottom line is, are we being treated equally on air in terms of which stories we are expected to cover.”

As co-host before Tom Bradby was appointed ITV’s main flagship news anchor last October, Etchingham typically sat on the left of Mark Austin and the right of Alastair Stewart.

Minchin, who has been on BBC Breakfast for 10 years and is nine years older than her new 38-year-old co-host, is understood to have wanted to sit on the left of Dan Walker, after Turnbull left. However, producers decided it did not work visually, partly because Walker is 6 feet 6 inches tall.

Minchin has not spoken out about the saga but a viewer, Adele Clarke from Cheshire, wrote to the Radio Times accusing the producers of sexism.

Etchingham said that an affair dubbed “sofagate” on twitter had at least shown some signs of change. “Traditionally it would have been a much older man and younger woman. Thank god that’s started to change, slowly.”

She paid tribute to O’Reilly for raising awareness about the continuing lack of older women on screen.

Male presenters tend to be placed on the left-hand side of their female colleagues on the BBC, including on the One Show in which Matt Baker tends to sit on the left of Alex Jones. On ITV theformat is used to seat Piers Morgan and Susanna Reid on Good Morning Britain and Phillip Schofield and Holly Willoughby on This Morning,.

Good Morning Britain made light of the fact that Morgan, a former tabloid editor far less experienced on television than Reid, tends to sit on the left when it tweeted:

Even when the ITV breakfast show brought in two children to echo the adult presenters, the little boy was placed on the left of the girl.

The rule is not watertight, however, with Eamonn Holmes occasionally appearing on the right-hand side of Isabel Webster on Sky News’ Sunrise, for example, and the channel’s Jayne Secker and Colin Brazier regularly swapping places.

Interesting to see this today in @DailyMailUK here at @SkyNews @colinbraziersky and I swap sides each day. pic.twitter.com/MVz8a70hQc — JayneSeckerSky (@JayneSeckerSky) March 16, 2016

The BBC Breakfast change caused a huge debate. One programme maker said there tended to be a perception that the more senior presenter sat on the left. “It’s not about gender but it may be about seniority,” said the source. “The presenter on the left is referred to as number one and the presenter on the right is number two.”

Cristina Nicolotti Squires, the editor of Channel 5 News, said that tradition put the man sat on the left, which may have become “subliminal”. However, she added that the “division of work” was far more important and also welcomed the fact that it was no longer always older men and younger women acting as presenting teams.

One BBC News presenter said there was often a “sense of entitlement” that the more senior person should sit on the left.

“It’s a curious thing, it does always seem to be regarded as the more senior position on the left although I have known people to swap around. Usually it’s the person who has been there the longest and established themselves in the more senior position – a sense of entitlement is very evident.”

But agent Jonathan Shalit, the chief executive of Roar Global whose clients include ITV presenters Lorraine Kelly and Kate Garraway, said he had never negotiated a contract stipulating where a presenter should sit.

“I have never had a conversation ever about who sits on the right or left, it doesn’t enter the equation,” he said. “I don’t think anybody on [ITV’s] This Morning thinks Philip Schofield is senior to Holly [Willoughby] but Philip is on the left. I think people get set in the way of doing things, it’s a tradition, it’s certainly not because of seniority.”

The former BBC presenter Shelagh Fogarty, who now presents a show on talk station LBC, said: “If anyone told me where to sit on the sofa I’d have said I’ll sit behind it because this is too ridiculous. If you asked me where I would prefer to sit on the BBC Breakfast sofa, I’d actually say on the right because it’s closer to the guest and you might regard that socially as an advantage.”

Industry experts said Walker’s height might also be a factor. At 6 feet 6 inches tall, it is more appealing to the eye if the taller person sits on the left. The BBC Breakfast studio in Salford is also very cramped, limiting the movement of the cameras around the two presenters and their guests.

In a statement, the BBC said: “There is no seniority in terms of who sits where on the BBC Breakfast sofa. It’s all about judging which is the best camera angle for the presenters.”

It also pointed out that BBC Breakfast’s main presenters include three women and one man.