Parental leave to become flexible under plans set out by Nick Clegg

Women are held back in Britain by "clapped-out rules" which discourage professional development after they take maternity leave, Nick Clegg will say as he unveils new plans for flexible parental leave.

The deputy prime minister, who will announce that both parents will be allowed to share up to a year's leave after the birth of a child, will say that new mothers face a narrowing of career options.

"We, as a society, we have got so much better at telling young women: the sky's the limit. Get a job; be independent; be the boss; run as far and as fast as your talents can take you," Clegg will say in a speech on Tuesday in Putney, south-west London.

"Then, suddenly, when they hit their late 20s, their early 30s, despite all their earlier momentum, despite all the endless possibility, they are suddenly stopped in their tracks. It's like a rubber band snaps these women back. Because, the moment they start planning a family, their options begin to narrow."

The deputy prime minister, who will highlight outdated rules on parental leave, will annouce that parents will be given the right to share the care of their child in the first year after birth. Women in employment will retain their right to 52 weeks of maternity leave. Only mothers will be allowed to take leave in the first two weeks' leave after birth. But after that parents can divide up the rest of the maternity leave.

Clegg will say: "From 2015, the UK will shift to an entirely new system of flexible parental leave. Under the new rules, a mother will be able to trigger flexible leave at any point – if and when she feels ready. That means that whatever time is left to run on her original year can be taken by her partner instead. Or they can chop up the remaining time between them – taking it in turns. Or they can take time off together – whatever suits them. The only rule is that no more than 12 months can be taken in total; with no more than 9 months at guaranteed pay. And, of course, couples will need to be open with their employers, giving them proper notice."

Clegg has, for the moment, abandoned plans to extend paternity leave in addition to the total time parents will have. Under pressure from the Tories and some business leaders, who feared this would impose a burden on business during the recession, he has agreed to revisit this once the economy has recovered.

But Clegg will announce that men will be given a legal right to take unpaid leave to attend two antenatal appointments. He will say: "Lots of fathers will tell you that these moments are when it can start to feel real for them. Whether that's at the 12-week scan – the first time they see their child on a screen - or a bit further down the track, when they can find out if they're having a girl or boy. This new right means no father will ever need to miss out."

Clegg will launch a scathing attack on the current rules. "The problem comes down to a whole range of clapped-out rules and arrangements. Whether that's the balance between maternity and paternity leave; or the childcare that's available; or the way our tax and welfare systems don't fully reward part-time work. Arrangements which assume that families are still comprised of one bread winner and one homemaker; mum in the kitchen; dad in the office. Even though the reality is that, in many families, both parents work, often juggling busy lives, often working part-time, often without relatives or friends close by who can help out."