17/05/2012 18:33 BST | Updated 17/07/2012 06:12 BST

Equal Pay for Women - 60 Years on

I was born the month that parliament voted equal pay for women.

A law that was less useful to my mum than it should have been because she worked in a low paid 'woman's job' as hospital cleaner for the 'pin money' that paid our bills. It was not until the 70s that I was able, as a young lawyer, to use a new Equal Pay Act to win equal pay for women in segregated jobs that were of equal value to men.

Even now the Equality and Human Rights Act (EHRC) estimates that my daughters may earn £361,000 less than men over their working life. But there is hope for my granddaughters. A 2010 survey of four year old girls in the UK showed they have great self-worth and believed themselves cleverer and more hard working than boys, in contrast to rural East Africa where girls value themselves less than boys, expect less and get less.

The starkest evidence of gender inequality was revealed by the pay gap measure within a joint report published last year, by Plan UK and the Royal Commonwealth Society. It highlighted that even in the best-performing countries, women earn only around four-fifths of male income on average. Despite decades of campaigning in Western Commonwealth countries, Rwanda and South Africa top the female political participation table - Rwanda ranks first in the world in this regard. The United Kingdom tied with Pakistan at joint 17th and we will stay there, until women either claim better pay for the caring jobs where we dominate or make different career choices.

Gender stereotypes start very young. Plan's 75 years of experience shows that to change the prospects of a girl or boy you need to change the world around them. But change is happening.

A cohort of 142 girls that Plan is following in nine developing countries shows that life is changing for women today. According to the group Mums in Uganda, "Things have changed drastically because of women's empowerment - women and girls put on trousers, own public offices, own property, eat chicken and talk in public places - unlike in the past when these things were for men and boys only". Traditionally it was not only men who wore the trousers but who ate the best parts of the chicken. The crucial difference however is made through education and 39 million girls are still out of school - not even starting on the ladder to equal pay.

Sixty years after the equal pay act, we still need to support our granddaughters and daughters to achieve the remuneration they are entitled to and stop society getting away with paying women less because they value their work less. In the developing world the issue is even more acute because women are more likely to put their increased earnings into their family, thus paying women fairly is crucial to breaking the cycle of poverty.

In Rwanda, where girls perform much worse than boys in the end of primary school test, we are working with parents to discuss the benefit to the family of educating a girl, training school management committees on girl friendly schools and training teachers on how to be sensitive to girls' learning needs.

Our annual Because I am a Girl publication this year focuses on learning from our work and that of other organisations on achieving access to education for the 39 million adolescent girls who are out of school. It tackles the causes; poverty, early pregnancy, violence in schools, domestic responsibilities or simply because their education is not prioritised by families. And we also examine how a good quality education can be delivered - one that gives skills for life.

We know that working to change the attitudes of those who have a duty to a child - the family, community, education service, and of girls and boys themselves - takes time. It is based on building trust in the community.

It involves documenting and replicating what works to get children in school, to keep them there and acquire the skills they need to break the cycle of poverty.

But in the meantime there are 500 million girls in the developing world - the size of the European Union - and a whole new generation, capable of moving themselves and their communities from a life of poverty to a future with opportunity, if given a fair chance.