Royal Mail workers have begun voting on whether to walk out in a dispute over salary rises that could become the biggest strike this summer, while tram drivers have begun a 48-hour strike in south London in a separate row over pay.
About 115,000 members of the Communication Workers Union (CWU) have received ballot papers and will vote in the coming weeks on whether to stage a campaign of industrial action. The result of the vote is expected on 19 July.
