Vodafone has called for greater transparency of global authorities after it revealed that governments around the world are using a variety of methods to allow them to listen in on mobile phone conversations.
Around 29 countries across the world, including several in Europe, have tracked Vodafone users and monitored phone calls, according to the company's first ever Law Enforcement Disclosure report.
The company said wires had been connected directly to its network and those of other telecoms groups, allowing agencies to listen to or record live conversations and, in certain cases, track the whereabouts of a customer.
Some government agencies even had "direct" and "permanent access" to Vodafone's infrastructure, the company confirmed, meaning they do not have to make a formal request in order to intercept calls.
Vodafone said it was releasing the report to provide "a detailed insight into the legal frameworks, governance principles and operating procedures" concerning its responses to demands for assistance from law enforcement and intelligence agencies across the world.
"In our view, it is governments - not communications operators - who hold the primary duty to provide greater transparency on the number of agency and authority demands issued to operators," Vodafone said in the report.
The company called for governments to "discourage agencies and authorities from seeking direct access to an operator's communications infrastructure without a lawful mandate".
During 2013, the UK government made 2,760 requests to intercept Vodafone customer data, out of a total 514,608 warrants for metadata such as the content of calls and messages to all UK networks.
Despite its apparent concerns, however, Vodafone said it would prefer to continue complying with surveillance requests rather than not operate in a country.
"If we do not comply with a lawful demand for assistance, governments can remove our license to operate, preventing us from providing services to our customers," the company said, adding that such a move could also put its employees at risk.
Vodafone said the report has been published as "questions have been asked about the role of communications operators such as Vodafone in support of those activities".
"Our customers have a right to privacy which is enshrined in international human rights law and standards and enacted through national laws," the company said, adding that it would look to update and publish the report annually.
"Respecting that right is one of our highest priorities: it is integral to the Vodafone Code of Conduct which everyone who works for us has to follow at all times."