Most people would be forgiven for thinking that the question of whether they had been injured was not one that would be too difficult to answer. But the courts have struggled for decades with the 'date of knowledge' provisions, now contained in sub-sections 11 and 14 of the Limitation Act 1980, and two recent cases highlight the difficulties.

In McCoubrey [2007] and Young [2006], the Court of Appeal considered the three key questions on the application of sections 14(1)(a) and 14(2).

Under section 11, a claimant has three years to bring a claim from the date of accrual or, if later, his date of knowledge. The date of knowledge is the date he first knew three facts, including the fact that the injury was significant (section 14(1)(a)). "An injury is significant if the person whose date of knowledge is in question would reasonably have considered it sufficiently serious to justify his instituting proceedings for damages against a defendant who did not dispute liability and was able to satisfy judgment" (section 14(2)).

These provisions raise the following questions:

does section 14(2) contain an objective or subjective test?;

what makes an injury sufficiently serious? Are the factors to be taken into account limited to its physical and psychological effects?; and

if the objective approach is adopted, what assumptions should the court make about the reasonable man?

Bryn Alyn [2003] appeared to have decided the first question in favour of a subjective test. The court asked when the individual claimant, with all his particular characteristics, history and circumstances, would have considered the injury sufficiently serious.

In McCoubrey and Young, the Court of Appeal, relying on the House of Lords' decision in Adams [2004], found that the subjective approach was wrong. It held that the particular character and intelligence of the claimant were not relevant to section 14(2) unless the injury had affected the claimant's character or intelligence.

The different results in Bryn Alyn and McCoubrey/Young arise from the application of the requirement in section 14(2) that the claimant would reasonably have considered the injury sufficiently serious. The Bryn Alyn approach is to emphasise the primacy of the claimant's judgement, whereas McCoubrey and Young make it clear that the objectivity imported by the word 'reasonably' is the key.

The second question is dealt with in McCoubrey. The judge found that a soldier who suffered deafness in 1993 acted reasonably in not regarding his injury as sufficiently serious to justify instituting proceedings until 2001, when his employer told him that his hearing problems might exclude him from active service.

At first glance it may appear that the judge was simply applying the subjective test. In fact, the judge approached the case differently. She widened the scope of the effects of the injury that are relevant to its perceived seriousness, either by the claimant or an objective observer. By taking into account the effect of the injury on the claimant's career, the judge was able to conclude that the seriousness of the injury only became apparent at a much later date.

The Court of Appeal disagreed: the seriousness of the injury was not to be decided by reference to its effect, even in objective terms, on the claimant's
private life or career. The judge ought to have focused only on what the claimant knew of the injury itself, rather than its consequences.

Although the question was not addressed directly in Young, it may be that the court assumed a wider approach applied. Lord Justice Dyson, for example, said the court could take into account "the inhibiting and other consequences of the injury" in deciding if it would be considered sufficiently serious, but did not expand on what those 'other consequences' might be.

The third question requires the court to make fine distinctions. If enough of the characteristics of the actual claimant are assigned to the reasonable man, he will be indistinguishable from the claimant – and the objective test will be a subjective test by another name.

In McCoubrey, Lord Justice Neuberger recognised that the reasonable man would not just have suffered the same injury as the claimant but would share the same objective circumstances. However, the judge also warned that this was unlikely to make any difference in the vast majority of cases, including the one in question, given the essentially limited and objective nature of the enquiry. Accordingly, in this area too the Court of Appeal has taken an objectivist approach and it is perhaps unlikely that the reasonable man's similarity to the claimant will extend beyond his age, sex and occupation.

So the question of when a person knows they have been injured is not so simple. The House of Lords is considering a petition to appeal Young. This saga may not be over.

Steven Ford and Sam Nafissi are barristers at Seven Bedford Row.