You won't win equality in your best frock

As part of Black History Month, 150 black and Asian women are asked to appear at a reception at the House of Commons, there to be held up as both role models and reminders to the country that we exist and can often be talented and ambitious - yet are still largely invisible in public life. You can see why I cringe at the thought of such a parade.

It is good to celebrate our achievements - just last week I went to the Women of the Year lunch, which is always exhilarating and makes me proud to be a woman. But this is not a celebration. Harman wants her reception to instigate real equality - and you don't do that in your best frock with a glass of wine in your hand. Trust me: it is not possible to kick down the doors that keep us out in a pair of Jimmy Choos. We need iron battering rams to force entry, and only tough policies will overturn the order.

It is a national disgrace that most public institutions remain stubbornly white and largely male. The Mother of Parliaments is the most potent symbol of this colour and gender privilege. Somehow, two black female MPs managed to sneak in, Diane Abbott being the first 20 years back. In 2007 there still isn't a single Asian woman MP. We must all be too busy making chapatis or something. Of nearly 20,000 local councillors, only 168 are black or Asian women.

Harman knows what needs to be done and is committed to this cause. The solution is some form of positive discrimination, even though the thought of that makes many grown men weep, including black and Asian blokes. At the Labour conference, when Harman mouthed the scary words, chaps in the audience shifted their bottoms so much they looked as if they were walking on them - a sure sign of their discomfort.

On Monday she could announce that a change in the law to allow positive discrimination is now seriously being considered by the Government in order to redress the democratic imbalance in parliament and local government. She could invite other public bodies and the private sector to support this radical shift. If she does that I will so regret not being there to cheer her on. If not, I hope she asks herself what the point is of the party - and if it isn't just a teeny bit patronising?