08/03/2016 09:05 GMT | Updated 09/03/2017 05:12 GMT

Whether We Leave or Stay in the EU, A Women's Bill of Rights Is Long Overdue

A year ago I proposed founding a new political party focused on gender equality. I did this because each successive international women's day reminds us not just what women have achieved but how many barriers still block our way. I also wanted to find a way to re-engage the multitudes of women who feel so excluded from the national political debate that they no longer exercise the very right Suffragettes fought hard to secure. Nine million women eligible to vote at the last election did not do so.

On 23 June, the UK again goes to the polls, this time to decide whether to remain in the European Union or to leave it. If the debate remains stuck in its current mode - puffed up male politicians posturing to secure the favour of their own party members rather than putting the national interest first - it would hardly be surprising if nine million women again stayed home. Yet this would also be a tragedy. One reason women are badly served by politics is that the views of women are poorly represented in the political process.

The Women's Equality Party aims to change that. That idea I voiced last year, a vision shared with Sandi Toksvig, has solidified into a substantial political force. We have 45,000 members and registered supporters and 72 branches, we're running candidates in the London mayoral and assembly elections and for the Welsh Assembly and Scottish Parliament in May, and today we celebrated International Women's Day by seizing the Europe debate.

We are calling for a Women's Bill of Rights to enshrine and extend the protections afforded to women by the EU. Leave or stay, such a Bill is long overdue.

Without question, EU membership has served British women well. A clause in the Treaty of Rome asserting the right to equal pay came to be interpreted as a wider right to equality, contributing to social progress and the improvement of living and working conditions for women across Europe. Together with the Equal Pay Directive this forced the UK to introduce and then expand its own national legislation on equal pay as part of its membership of the EU.

The wider legislation that followed, such as maternity leave, was significant too. Prior to the implementation of the EU maternity leave law, women in the UK were not eligible for maternity leave unless they had worked for the same employer full time for two years or part time for five years. The change in legislation expanded the rights to leave for 45% of British working women.

These rights must be protected in case of Brexit. The Leave camp claims there is no need to worry. The history of the struggle for women's rights tells us there is every need. Rights are more easily rolled back than they are won.

Yet this is not to say all criticisms of Europe are wrong. The EU was and is lacking in ambition for its female citizens. The driver of these changes was never primarily a concern for women's wellbeing but worries that competition between business would be distorted by irregular implementation of equal pay legislation. Similarly, faced with high unemployment, many European countries saw maternity leave as an opportunity to open up jobs to those who needed work without having to increase their national debt.

What Europe overlooked - and successive UK governments also seem too easily to ignore - is that enabling female participation in the labour force creates an economic windfall for the entire population. If gender segregation of jobs was reduced and women's employment was increased, it could be worth an extra £23billion to the UK economy alone.

Moreover Brussels and Westminster alike tend to recognise only the needs of those women in full-time employment and to do even less for the many women in part-time or insecure work or unemployed (though often jobless women work flat out caring for family members).

Our party model is about finding common ground; most parties at very least pay lip service to the benefits of gender equality. We opened membership to members of all other parties and we have members from all of the main parties. We rigorously keep our focus on gendered issues - and far from making us a single-issue party, this means our remit is huge. Gender inequality permeates every area of life. Our elected representatives will be bound by our six core objectives - equal representation, equal pay, equality through and in education, shared opportunities and responsibilities in parenting and caregiving, equal treatment by and in the media and an end to violence against women. On all other issues they, and our wider membership, have freedom to choose and define their own positions.

On Europe this means a free vote. I will cast mine to remain in Europe, as I would rather the UK government spends its energy - and money - on a drive for gender equality, instead of struggling with the consequences of Brexit.

Whatever the outcome on 23 June, women will only win with a Women's Bill of Rights.

Catherine Mayer is the president and co-founder of the Women's Equality Party