Bitter divisions in Labour over public-private partnerships have spread to Brighton, causing fears that members on the left will seek to deselect centrist party councillors.
Left-wing Labour figures in the city are furious at council plans to build 1,000 homes in partnership with a private enterprise.
Among the protesters is Kevin Allen, a left-wing local councillor and Momentum member, who said he had worries about the proposals and whether Hyde Housing, which was founded as a housing association, had “lost some of its social purpose”.