The latest available figures show authorities accessed more than 40 private communications each day in 2010 — compared with 31 per day a year earlier.

In 12 months, almost 15,000 requests were made of telecom companies to hand over details of private citizens’ activity.

This represented a 32% spike in state-authorised spying of electronic communications. And it broke through the high of 14,095 requests made in 2008.

The increase was largely due to a substantial shift in demand for access to people’s internet activities.

In 2010, there were 4,464 demands for internet traffic dealt with, compared with 1,502 in 2009 and 2,872 in 2008.

The statistics were released by the Department of Justice ahead of the publication of Europe-wide figures under the data retention directive. They showed the majority of details sought by the authorities related to recent contacts — 10,962 were less than three months old.

Fixed-line records were far more likely to be recalled within three months, while a significant minority of mobile data used in investigations was over a year old.

Separately, two reports on the operation of covert surveillance by the same three state bodies has revealed the extent to which the Garda and Revenue Commissioners have employed bugs and tracking devices to monitor criminal gangs and international smugglers.

It showed that in the first two years of the Criminal Justice Surveillance Act there were almost 200 occasions where tracking devices were deployed by gardaí who had used bugs to monitor the activity of subversive organisations and criminal gangs.

The Revenue Commissioners have also used tracking devices that helped lead to the detection of at least €35m-worth of illegal cigarettes smuggled into Ireland.

The surveillance activity is covered under separate legislation to the tapping of phones and data retention powers. This policing work is governed by new domestic laws that built on the European data retention direction.

The 2010 figures for the directive showed that on only four occasions were companies unable to supply the data looked for, compared with 92 in 2009.

The firms have said a memorandum of understanding between them and the state authorities has been effective.

ALTO is the representative body for eight independent telecommunications providers, including BT Ireland and O2.

Chairman Ronan Lupton said in most cases the officer who was requesting the information would be known to the designated telecom worker who retrieved the data.

However, he said there were issues with its operation, such as the lack of clarity on what to do with records that had already been retrieved by authorities.

Currently, once data is identified, it is retained indefinitely in case an investigation might progress in the future. More than 40,000 records were pulled out between 2008 and 2010. Ordinarily, all records are deleted after one or two years.

The Government-appointed referee for the data retention legislation, Mr Justice Iarfhlaith O’Neill, has filed a report to the Department of An Taoiseach on the operation of the act in 2010.

He said he was satisfied it was carried out properly but expressed reservations that, since the merging of the portfolios of justice and defence, Minister Alan Shatter had been ultimately responsible for requesting information under one function (defence) and authorising it under another (justice).

This has since been addressed.

Read more in this special investigation here.

[View the story "Invasion of privacy: Special investigation" on Storify]