The Trade Justice Movement and the Core Coalition have formed a strong team.
Partnership working between two organisations can present difficult challenges, but when the Trade Justice Movement teamed up with the Corporate Responsibility Coalition (Core), more than 100 not-for-profit groups were involved, from charities to trade unions and churches to social enterprises.
The huge alliance was formed last year to bring civil society pressure to bear over the content of the Companies Bill, the biggest change to corporate law and the legal responsibilities of company directors in 150 years.
The Trade Justice Movement already had experience as an integral part of the best-known voluntary sector coalition of the past decade - Make Poverty History. In November last year, alongside MPH, it organised one of the biggest lobbies Parliament has ever seen.
"One of our hallmarks is capturing the public imagination on global poverty," says Glen Tarman, co-ordinator of the Trade Justice Movement. "Each coalition could bring its different areas of expertise - we would lead on public mobilisation and Core would lead on detailed policy and parliamentary questions. Core has the relationships with lawyers, we have the relationships with activists across the country."
It is a division of labour that seems to have served the campaign well.
Core has worked with MPs and lawyers (some working anonymously on a pro bono basis) to develop amendments to the Bill requiring company directors to protect the environment and workers' interests. The Trade Justice Movement has kept up the pressure at Westminster, persuading more than 100,000 people to lobby their MPs about the Bill.
For Core co-ordinator Hannah Ellis, the two-pronged approach has shown the value of coalitions that can draw on the varied skills of their members.
"The campaign has illustrated how a diverse range of groups working together can become much more than the sum of their parts," she says. "With complicated and ambitious campaigns, a broad spectrum of alliances and expertise is essential.
The campaign is approaching a crucial stage. The Companies Bill returns to the Commons next month. The coalition says it will "mobilise a huge amount of support" to try to persuade the Government to accept that firms have wider legal obligations than making profits for shareholders.