Then we turn into Farringdon Road and facing us, head on, is an advertising billboard for Do It All, the DIY chain. A wall of locks and chains and bolts is topped with the words 'Lock up your daughters'. Suddenly I feel so angry and insulted by it that I quite surprise myself. Sure, it's a joke. OK, it's referring to a famous play. But actually, it's not OK.
This has been a fascinating week for feminist politics. We have stuck our head above the parapet to announce our anniversary - and then we listened to the response. Among the brickbats and bouquets has been a strong sense that it's time to move on, that soon Virago, 'a victim of its own success', will have made itself redundant. (We are already redundant, according to the Daily Telegraph; we have 'come to denote nothing more threatening than beautifully packaged paperbacks conforming to an ethos as dated as dungarees'.)
It's not even anything to do with post-feminism. It's just the feeling that talking about the rights of women is unfashionable and anachronistic. And that worrying about sexism in advertisements is certainly out-of-date and faintly embarrassing. After all, life has improved enormously for women, hasn't it? Look at Virago, for example . . .
We live in a climate where to be 'politically correct' is the ultimate put-down. Of course it's easy to sneer at 'vertically challenged' and all those other PC catchphrases. But it is not a sniggering matter if as a result questions of equality and humanity become so trivialised that they do not have a proper, intelligent forum - and people take it as a sort of tacit permission to be sexist and racist.
In this climate, strong and confident women's presses and bookshops are essential. Some people call the Virago green livery a ghetto. I call it the stylish and highly visible evidence of women writers and publishers who boldly continue to call themselves feminists. I don't mean to suggest we are the only people who care about the injustices of the world - far from it. But we are a high-profile representation of a large body of opinion.
Even the complimentary press pieces on Virago have been revealing. Some show that even if Virago is now part of the literary establishment, a feminist perspective on the world is not as firmly established. The Observer, for example, illustrated its article with a painting of Judith and Holofernes by Artemisia Gentileschi showing two women brutally slitting a man's throat with a knife and captioned 'Women's Work'.
Feminism can be authoritarian - we know that, and have tried not to impose a censorious feminism at Virago. I have always seen feminism as a sort of code for the way we live, the way we engage with each other (particularly with the opposite sex) and the way we make sense of our lives. I like to think of it as a vision of what is best in all of us. There may be a fine line between the critical voice and the censorious one, but there is an important distinction.
Events like the Virago celebrations - and they have been glorious and people have been generous and kind - are in danger of masking an insidious complacency about women's position. All around are images and references to women that, I feel, tell a powerful, unpalatable truth about the way women are still seen by society. Let's not be cowed by the fear of being called politically correct, let's get our priorities right instead. What does a young girl think when she sees 'Lock up your daughters?' I reckon she thinks, 'Why should I be locked up, Mum?' Call me an old-fashioned feminist, but I don't want my daughter - or my son - to be locked into a world of stupid and offensive thinking.
The writer is Publishing Director of Virago PressReuse content