Let's not pretend that the Irish government were acting to protect our privacy however - they already force Irish ISPs to retain communications traffic data for three years. Their stance was political, standing against the use of market harmonisation procedures, with their use of qualified majorities, for matters which ought to be dealt with unanimously as police matters.
The judgement implies that retention of our data is a commercial matter, and not a policing matter; but far more fundamental - as we and forty one other human rights and privacy organisations argued to the court is the incompatibility of this directive with human rights law.
Our privacy is recognised by European and British courts as a matter of right. The European Human Rights Convention states quite clearly that we have a right to a private life and correspondence, and the European Court of Human Rights has stated that traffic data is ‘an integral element in the communications made'.
We argued at the time that the Irish government started their case that the Directive should be rejected on purely human rights grounds. Now that this argument has in effect been finally rejected, along with the Irish government's political pleas, it's worth going back and seeing what human rights organisations said to the Court. I've selected here just a few ways that data retention could lead to abuses in a very real way. (It's a long document but well worth looking at in full. Some of the problems may well come back to bite us in years to come.)
Furthermore, retaining traffic data creates potential risks of abuse by state agencies. Traffic data can be extremely useful for political control, eg by intelligence agencies. Experience shows that the risk of powers being abused, especially where they are exercised in secret, must not be underestimated even in Europe.
Furthermore, where the government prevents the effective protection of personal data because of its appetite for surveillance, it opens up the gates for misuse of the data by third parties. Innumerable facts about the private life of prominent members of the public could be obtained by analysing traffic data. In the event of unauthorised access to retained traffic data, politicians could be forced to resign and officials could be blackmailed.
Where data retention takes place, citizens constantly need to fear that their communications data may at some point lead to false incrimination or governmental or private abuse of the data. Because of this, traffic data retention endangers open communication in the whole of society. Individuals who have reasons to fear that their communications could be used against them in the future will endeavour to behave as unsuspiciously as possible or, in some cases, choose to abstain from communicating altogether. Such behaviour is detrimental to a democratic state that is based on the active and unprejudiced involvement of citizens. This chilling effect is especially harmful in cases which attract abuses of power, namely in the case of organisations and individuals who are critical of the government or even the political system. Blanket traffic data retention can ultimately lead to restricted political activity, bringing about damage to the operation of our democratic states and thus to society.
Traffic data retention also causes increased efforts in the development of countermeasures such as technologies of anonymisation. Where the state indirectly encourages anonymous communications in its pursuit of surveillance, it will ultimately damage its power to intercept telecommunications even in cases of great danger.