Mobile phone operator Vodafone has admitted to allowing the monitoring of calls of its customers world-wide.

According to The Guardian, the company says secret wires are directly connected to its network that allow government agencies listen to or record conversations and - in some cases - track the whereabouts of a customer.

The surveillance is used widely in some of the 29 countries in which it operates in Europe and beyond.

The company has revealed the practice in a bid to stand up against the increasingly widespread use of phone and broadband networks to spy on people.

It has also published its first Law Enforcement Disclosure Report.

Within the report, it says that while it cannot disclose the number of "lawful interception" of communications in Ireland, it has seen a demand for 4,124 worth of "communications data" here.

By comparison, Italy made 139,962 interception requests in total and 605,601 communications requests to Vodafone alone. In the US, Verizon said it received 321,545 requests for customer information.

It adds that while Irish law does not expressly prohibit the disclosure, Vodafone say they asked the Irish authorities for guidance and were informed they could not disclose this information.

Some of the figures are being disclosed by Vodafone for the first time, including those for Spain and Tanzania.

The report also lays bare just how much communications data - often referred to as 'metadata' - can reveal about a person.

"It is possible to learn a great deal about an individual's movements, interest and relationships from an analysis of metadata…In many countries, agencies and authorities therefore have legal powers to order operators to disclose large volumes of this kind of communications data".

Vodafone said it was publishing the report because "questions have been asked about the role of communications operators such as Vodafone in support of those activities".

The company says the report - which is the first of its kind published anywhere in the world - consists of a detailed overview of the legal, governance and operational factors of intelligence agency access to customers' private data, a country-by-country breakdown on the volume of demands made by government authorities, and a legal summary of the most relevant legislation governing agency and authority access to customer data in each of Vodafone's 29 countries of operation.

It says that this information has not previously been published by any operator.