TRAM workers in Edinburgh facing “unacceptable” conditions have overwhelmingly backed strike action.

More than 90 per cent of Unite members at the service, owned by Edinburgh City Council’s Transport for Edinburgh, voted to take industrial action in a dispute over late running times to Scotland’s largest airport and the prevention of workers from taking comfort breaks.

The union argues a troubled new signalling system leaves workers unable to take toilet breaks for as long as five hours, causing stress and infections among its 160 drivers, ticket service assistants, controllers and vehicle maintenance workers.