When a recent Radio 4 discussion asked why more women are not shaking up the boardrooms of Britain’s top companies, the panel was stunned to hear Janet Street-Porter announce that the real issue was self-esteem. Despite running a television channel, managing multi-million-pound budgets and editing a national newspaper, she said that she had struggled to be taken seriously. “Believe me, I am not without self-doubt,” she confirms to me. “I come packaged as someone with confidence, but the reality is different.”

It seems she is not alone. Baroness Shirley Williams wrote in her new auto­biography that she’d always thought of herself as “not quite good enough” for the top job. Victoria Beckham, meanwhile, recently admitted that she, too, suffered from feelings of self-doubt. “I do have my insecurities. Maybe that’s why I often look a little bit serious,” she said.

Can women’s poor showing in big business — they make up only 9% of board members of FTSE 350 companies — really be down to lack of self-belief?

Suzanne Doyle-Morris, an executive coach and author of Beyond the Boys’ Club, a survival guide for female high-flyers, is adamant that confidence is a huge issue. “A lot of women suffer from what’s known as ‘impostor syndrome’ — we feel we’re not good enough at our jobs, that we don’t deserve our success. Women are more honest about sharing those feelings with colleagues and it can backfire. Also, we’re reluctant to appear boastful. In our personal lives we’re so used to saying ‘Oh, this old thing’ when people give us a compliment. But we need to learn to operate differently at work.”

Doyle-Morris believes too many women still fantasise about being recognised as an “unsung hero” who will eventually be rewarded. “It goes back to the way we were brought up. The girl who bragged at school didn’t have friends for long. For many ambitious women this reticence also stems from a misguided belief about the value of keeping one’s head down. But it is the way you draw attention to what you achieve that sets you apart.”

The executive coach Peninah Thomson sees far less confidence among the women than the men she coaches. “One woman I was coaching actually said to me, ‘I don’t want to act like I’m the great I Am. If that’s what I’ve got to do to get ahead, I don’t want to go there.’ Men, on the other hand, find it a whole lot easier to use the ‘I’ word than women do.”

Street-Porter thinks that even if women start off confident, many will have that belief knocked out of them. “A lot of women who do get to board level find it hard to be taken seriously. I know I did. Men often have a secret agenda sorted out beforehand, little chats at the rugby club or watching the cricket, for f***’s sake. Things are decided in advance and women are not invited. I also think that when women are opinionated about how a company should be run, they are described as aggressive, whereas when it’s a man, he’s viewed as forceful and focused.”

Saira Khan, the former star of The Apprentice who now runs her own internet business, miamoo.co.uk, says there are two big reasons why women doubt themselves at work. “First, the workplace zaps women’s confidence because it’s not designed for us. Second, there is a chronic lack of female role models in business who normal women can relate to and be inspired by.” She cites the female panellists who appear on The Apprentice: You’re Fired as examples of high-profile figures who undermine the confidence of ordinary working women. “They’re all formal suits and cleavage, looking like they’ve just stepped out of a car wearing a big diamond. That whole idea of the big shoulders and the high heels, it’s so 1980s. Feeling you have to look like that makes women opt out.”

This idea of drawing attention to themselves seems to freak out a lot of women, and not without reason. “Women come under more intense scrutiny than men,” says Thomson. “They can feel uncomfortable stepping into the limelight, and success is not guaranteed.” Doyle-Morris agrees, and points out that it’s not only our clothes, make-up, weight and style of speech that come under the spotlight, what we chat about is also being judged. “Women are surprised when I tell them to tone down some of the talk about their personal life. Typically, men use talking about sport as a ‘safe’ topic that they can bond over. Women don’t have that; they’re more likely to discuss personal issues, and people at work can use that against you.” She cites the case of one client who visited the office while on maternity leave and mentioned to colleagues that she was having trouble finding a nanny. “It was a throwaway remark that was seized upon and turned into gossip that she might not be coming back. I’m not saying don’t make friends at work, but don’t talk about your dating life or problems at home until you know you can trust them. Better to stick to The X Factor and holiday destinations.”

Can the reason for women’s inability to reach the top really be only about self-belief? Recent research also points to other factors. As well as the much-touted “glass ceiling”, we’re now also apparently dealing with “sticky floors”, “labyrinths” (management structures where women are destined to get lost) and, most devious of all, “glass cliffs”. The latter term was coined by the University of Exeter to describe the practice of promoting women to “dangerous” jobs that leave them exposed to failure and, ultimately, a gilt-edged P45.

Khan fears that only a radical change of the workplace is going to entice working mothers into the boardroom. “As a model, it doesn’t work. More and more women, especially mothers, are opting out and setting up as mompreneurs. They work really hard, but they have more control. Personally, I work round the clock now, but I still have a better work/life balance, which makes me happier than I ever was in the corporate world. And I have to say, nothing boosts your confidence more than being happy. It’s so easy to forget that.”

Don’t Let the B*****ds Get You Down by Janet Street-Porter (Quadrille £12.99)

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