Christine McCarthy makes the case for having phones in cells:
Telephones in prison cells are becoming the norm in countries such as England and Wales, Scotland, Ireland, France, and Belgium. The European Committee for the Prevention of Torture and Her Majesty’s Inspectorate of Prisoners in the UK both welcomed this. In New Zealand, only the Serco-run Auckland South Corrections Facility has in-cell telephones, which the Ombudsman has supported.