Thousands of Royal Mail workers have staged a rally to mark another strike in the increasingly bitter dispute over “unachievable” conditions they said would “destroy” the company.Members of the Communication Workers Union (CWU) from across the UK congregated outside Parliament in central London to voice their anger about the proposed changes they believe would turn them into “gig” economy workers.CWU general secretary Dave Ward told the PA news agency: “They’re fighting for their jobs, their livelihood, and the service that they provide to the public.