Returning after maternity leave - what to expect
After the birth of her third child in 2005, she says, senior civil servants were clearly displeased that she'd taken maternity leave, changing her responsibilities and working arrangements while she was away.
"It is illegal to treat staff unfairly while on maternity leave. But most women don't know the law and don't feel able to challenge. So experienced and skilled women are pushed out of jobs or lose pay when they feel least able to disagree," she wrote in the Independent.
"We need national action to deal with maternity discrimination, including tackling irresponsible employers who are breaking the law."
So what are a woman's rights when returning after maternity leave, and what should you do if you feel you've been discriminated against?
In principle, women have the right to go back to the same job with the same pay and conditions as before. But you may have to put up with some changes: a lot can happen in an organisation over six months or a year, and your employer is allowed to offer you a similar job instead, as long as the pay and conditions are the same. If this can't be done, you may be entitled to redundancy pay.
On the up side, it's worth noting that holiday pay builds up while a woman is on maternity leave at the same rate as if she had been working throughout - making for a useful extension to the maternity leave itself. And there are concessions to the difficulty of the juggling act required from most new parents, such as the right to request flexible working - though this can be refused where there's a good business reason.
In addition, staff who have completed a year's service with the organisation have the right to take up to 13 weeks unpaid leave up to their child's fifth birthday, or up to 18 weeks where the child is disabled and under 18.
If you believe you've been unfairly treated, the first step, of course, is to speak to your employer and if necessary make a complaint through the organisation's standard grievance procedure. If that doesn't work, it's time to approach your union, if you have one, or the Advisory, Conciliation and Arbitration Service (Acas).
Unfortunately, though, the government recently introduced a £1,200 charge for women to take a maternity case to a tribunal - something Labour strongly opposes.
And it's not always easy to know whether you've got a strong enough case. Sometimes discrimination is clear and outrageous - like the Barclays employee told she couldn't have the same job back after maternity leave last year because she wouldn't be up to the heavy workload. Often, though, it's more subtle.
In a survey carried out by law firm Slater Gordon last month, more than half of women returning to work after maternity leave said they felt that their employers' and colleagues' attitudes towards them had changed, with two thirds saying things had become 'difficult' after returning. Three in ten thought they'd missed out on promotion because of being a mother, and 42 percent felt those younger and without children were prioritised in the workplace over themselves.
Such problems can appear hard to challenge, but Slater Gordon lawyer Kiran Daurka says it can still be done. "With all these smaller, subtle things, you can still build up a picture of discrimination," she says.
"If you have suspicions or concerns, keep a diary. Look at your career plan before, and now. It's always useful to compare yourself with other people; say, before the pregnancy you were on the same level as them, and now you're not. Speak to other women in the organisation who have taken maternity leave - is there a pattern?"
Daurka warns, though, that the process of making a complaint or going to a tribunal can be extremely stressful and time-consuming - at a time when most women feel they've got enough to be dealing with anyway. And the chances are, she says, that you'll find yourself needing to look for another job.
"With nearly all the cases that we see, they settle for an unfair termination package and a gagging clause," she says.
"I think for the majority of women, the ideal outcome would be to keep the job with no discrimination, but if you're in an organisation where you don't feel you're valued, the best outcome is probably a termination package."
Yvette Cooper says that the Labour party is currently consulting on ways to make sure new mothers get a better deal. Scrapping the £1,200 fee women are expected to pay in order to get justice might be a good place to start. "I really hope it doesn't put people off - but I think it will," says Daurka.