Johann Hari: Sir Alan, sexism and the workplace

Watch 'The Apprentice' and see how even the hardest Sugar melts when in hot water

Hidden away in the crumpled forehead and gruff barks of Sir Alan Sugar, there is a parable about how to drive sexism out of the British workplace. If you want to understand how Harriet Harman's new Equality Bill will work, watch The Apprentice – and see how even the hardest Sugar can melt if it is dropped into hot water.

On the BBC reality show, 12 clawing, cloying young businesspeople compete for the right to sit at SrrrrAlan's feet and lick up £100,000 a year along with his entrepreneurial wisdom. But in series after series, he has made strange choices – which seem to veer in one direction. The final two contenders are almost always a likeable but mediocre man, and a fantastically clever and hard-working woman. The choice seems obvious to a watching nation – until SrrrrAlan boots the woman and hires the man.

Workplace sexism is incredibly hard to prove in any individual instance. Maybe somebody really would prefer squawking Lee over hyper-efficient Claire. Maybe a boss sincerely would prefer nice-but-dim Simon over clever Kristina. How can you be sure?

It becomes plain only when there is a pattern – and with SrrrrAlan the pattern was plain. He has repeatedly asked women about how they look after their children, and when they tried to explain, he said: "I'm getting worried here." He even told an interviewer that in everyday business life, "you're not allowed to ask [about their children], so it's easy – just don't employ them".

So the woman lost the job to a less competent, less impressive man. It happens in the offices of Britain every day. A study this weekend by the Higher Education Policy Institute found that women outperform men at every stage in higher education. But as soon as they enter the workforce, this is immediately wiped out. For the same work, women now earn 17 per cent less in full-time positions, and 40 per cent less in part-time jobs. The Alan Sugars blame this on them having babies – but it's not true. How do we know? Because the pay gap is in place and fully grown before they have their first child.

This is bad for everyone in Britain, including men like me – because our companies aren't being run by the most talented and hard-working candidates. The only woman who has ever won The Apprentice, Michelle Dewberry, says: "It's not just Alan Sugar – there is this male mentality, which is that when they interview a lady, they look at her as a baby-making machine."

Harriet Harman's Equality Bill is an attempt to shame bosses into turning this around – and we know it will work, because a similar process has changed even a T-Rex like SrrrrAlan.

The Bill requires companies to calculate the gap between what women are paid and what men are paid in their organisation, and publish it. Some companies have squealed that their gap will be large, because their managers are overwhelmingly male, and their cleaners are overwhelmingly women. Well, yes. Do you think women are better suited to scrubbing than managing? Do you want to make that case to the public?

Many companies will face a firestorm about sexism – and most will be embarrassed (or panicked by potential law suits) into turning their companies around. Alan Sugar has. After last year's bush-fire of negative publicity, four of the five finalists this year are female. Startled by the public contempt, Sugar seems to have started assessing women with a more open mind. If it can happen to Alan Sugar – a man who asked questions that bordered on illegality just a few years ago – it can happen to any boss.

The final four female contestants this year show how foolish it is to stereotype women in the workplace. Kate Walsh seems consensual and soothing yet always gets what she wants. Debra Barr is an ultra-aggressive fighter who rhetorically stabs anyone who gets in her way. Yasmina Siadatan is a do-it-cheap, sell-it-fast corporate girl. And Lorraine Tighe is a Matalan-clad Cassandra, endlessly declaring the task is doomed to fail before it's even begun. What do they share, other than business acumen?

David Cameron has come out against pay audits, and tried to scupper the Equality Bill entirely. He wants a company to have to publish its pay gap only in the very rare cases where a woman has fought a sex discrimination case and won. So instead of every company doing it, virtually none will. The message to every woman in Britain is clear: David Cameron doesn't want you to know if you're being ripped off at work.

But the Labour policy of mandatory pay audits only gets us part of the way – and it comes 12 years too late. If we are going to use women's talents to the max, we need a parallel reform that only Nick Clegg, the Liberal Democrat leader, has had the guts to talk about it publicly. Today, women are entitled to 52 weeks' maternity leave after a baby is born, while men are entitled to just two weeks. This silently encourages the Alan Sugars to discriminate – but the solution is not the repeal of maternity rights.

In Iceland, they equalised maternity and paternity leave in 2003, and really encouraged men to take the time off to bond with their babies. The result has been a pay gap narrowing faster than in any other developed country – and they are nearly at equality.

Yes, it costs money to let men take time off – but it costs even more money to squander the talents of half the population on jobs that are beneath them. When Norway ruled that 40 per cent of all seats on corporate boards must go to women, growth shot up. When McKinsey studied the effect of having women in senior positions, they found it boosted stock-price growth by 53 per cent. Boosts like this pay for increased paternity pay several times over.

At a bleak hour, here is a way to dramatically improve our country, if only we will seize it. If we demand a few meaty legal changes, this can finally be an island where the Claires and Kristinas aren't wasted anymore, but instead hear that sweet sound from their bosses: "You're hired."