Human rights campaign group Liberty has described the findings of Vodafone's report into the extent of government phone-tapping as "terrifying".
Vodafone said some 29 countries in Europe and beyond use a "secret wires" system to monitor phone conversations and track users through their mobile phones.
Shami Chakrabarti, director of human rights campaign group Liberty, said: "For governments to access phone calls at the flick of a switch is unprecedented and terrifying.
In Albania, Egypt, Hungary, India, Malta, Qatar, Romania, South Africa and Turkey it is unlawful to disclose any information related to wiretapping or interception of the content of phone calls and messages, Vodafone said.
In six of the countries in which Vodafone operates, phone-tapping is actually a legal requirement. The phone company said it will not name the countries involved because "certain regimes could retaliate by imprisoning its staff," The Guardian reported.
More top news
The advertising watchdog has ruled the "beach body ready" campaign was not offensive or socially irresponsible.
Britain is set for the hottest day of the year today, with temperatures forecast to hit up to 34C (93F).
The Airports Commission is to publish its report and recommendations on whether an extra runway should be built at Gatwick or Heathrow.