TJ McIntyre writes:
There is a general rule in Irish law that illegally (not unconstitutionally) obtained evidence may be excluded at the discretion of the court. Yvonne Daly provides a very good summary of this rule in this article (PDF), where she points out that in practice this discretion is very seldom used to exclude evidence on the basis of mere illegality. I have been unable to find any reported decisions of the Irish courts dealing specifically with evidence obtained in breach of data protection law – however, in light of the discretionary nature of the exclusionary rule and the general tendency towards admitting illegally obtained evidence there is no guarantee that the courts will prevent this evidence from being used.
This is not, however, an end to the matter, as an employee may be able to achieve the same result indirectly by going to the Data Protection Commissioner.
Read more on IT Law in Ireland.