The Campaign For A New Workers' Party was an initiative of the Socialist Party of England and Wales that argued for the establishment of a new mass workers' party, involving trade union activists, socialists, anti-capitalists, anti-war and environmental activists. It was launched at the party's annual Socialism event in November 2005. There were more than 4,000 signatories to the campaign's founding declaration, many of whom were trade unionists. Some left parties claimed that the CNWP was a front for the Socialist Party.