Radical bookshops

Grassroots Bookshop in Manchester was one that I really liked and over the years I have been to radical bookshops in other cities, such as Leicester, Bristol and London.  Grassroots Bookshop of Manchester is no more, I understand.  Human rights is one of the topics addressed by books in these shops.  Also they can be good places to find notices or leaflets about events and campaigns.  Have people got any recommendations of shops like this?

Thanks, Wily Fox, for the comments and the link to the Amnesty event on 18 October 2008 (Words to Freedom) at Manchester Literature Festival.  Another event slightly later on the same day at the festival is on women's changing lives in China.  There is yet another event that evening with two authors talking about their latest novels which both offer perspectives on slavery.