Our legal system contains the idea that time runs. What is meant by this, is that an event triggering a cause of action is the beginning of a window of opportunity to litigate a claim. By implication, the window has an end point as well as a start point. A plaintiff cannot successfully commence litigation until the triggering event (the suffering of a loss, usually) and cannot successfully commence litigation after the expiration of the time allocated by the Statute of Limitations for that class of claim.
Notoriously, Ireland diverged from the UK by establishing two (2) years as the window of opportunity for litigating claims for personal injury. We used to provide 3 years. The UK still has a three (3) year time period for such claims.
The facts of any particular case may complicate matters considerably. Frequently, a claim might be made in contract or in negligence or both, and there might also exist a claim under the Product Liability Directive (and therefore the Liability for Defective Products Act 1991)
The Statute of Limitations provides for 2 years for the claim in negligence and 6 years for the claim in contract. However, the courts have ruled that a negligence claim for personal injury may not be run under the law of contract because that would circumvent the shorter period of 2 years. It is permissible to plead the terms of the contract and to prove the breach but only if this is done in proceedings commenced within the 2 year period.
Time, for these purposes, commences to run when the plaintiff knew or should have known of the damage (and the identity of the defendant).
A claim under the Product Liability Directive (and therefore the Liability for Defective Products Act 1991) is treated differently. All rights conferred by the Directive on the injured person are extinguished on the expiration of the ten year period commencing when the product was first put into circulation. (“The Long-Stop”). Commencement of proceedings within the ten year period eliminates the long stop as a defence. This requires that a plaintiff knows or discovers the date when the product was first put into circulation in a timely fashion; the commencement of the circulation might have happened years before the plaintiff was supplied with the product.
Within Ireland, it has been a live subject of discussion on the running of a time period while a plaintiff did not know that the time was running and could not possibly have discovered it. There is a strong argument that such a provision cannot be fair and therefore cannot be constitutional.
In the UK a similar argument was floated in the fetal anticonvulsant litigation with reference to the UK Human Rights Act 1998, but not pursued.
However times change and it is possible that the idea may surface in new circumstances.