Call centres
Call-centre staff were last month invited to report bad bosses to the TUC via a freephone hotline.
The initiative was part of the TUC's "It's your call" campaign allowing Britain's 400,000 call-centre workers to get free advice on workplace rights and report bad employers.
A TUC report published to coincide with the campaign states that unionisation among the 400,000 employees in call centres stands at 44%.