The most significant finding in what proved to be an interesting industrial deafness claim heard at Middlesbrough County Court recently, was that a company employing lorry drivers would not have known of the potential dangers of exposure to noise until 1972, much later than the usually accepted date of knowledge of 1963.

For years, insurers and their solicitors have had to face deafness claims where investigation proved difficult or impossible. If a plaintiff came along, often up to 30 years after he had started working for the defendant, he seemingly needed only to provide a skeletal description of his work to prove his case.

But in Craven v Tonks Transport, Craven was unable to accurately identify the types of lorry he had driven. The judge called his evidence "confused and confusing" and bore this in mind when also finding against him on limitation. The judge simply held that the plaintiff had failed to prove his case from the outset.

Evidence given by the plaintiff revealed that his wife and children had complained about his hearing problems for several years, and the connection with his job was made when he said he had told his wife the lorries were noisy. This was taken to be his date of knowledge.

It is reassuring to note that the judge looked beyond the usual alleged trigger points for knowledge: instructing solicitors or attending the medical. The defendant's difficulty in providing evidence actually favoured it when the judge considered his s33 discretion. If, he said, the claim had been pursued within three years of the plaintiff knowing he had a possible claim, the defendant could properly have dealt with the claim, an opportunity now permanently taken away.

The decision keeps limitation at the forefront of deafness claims and plaintiffs may now have difficulty providing a convincing explanation for the delay in bringing proceedings to set against the prejudice which defendants will suffer. The date of knowledge of the defendant was fixed, after hearing expert evidence, at 1972. Noise and the Worker, the pivotal document published in 1963, would not, if it had been read by the defendant, have signalled that the problems of industrial noise were their concern; only in the later Code of Practice published in 1972 was there sufficient such indication.

The case is a reminder that nothing should be taken for granted in these claims and that there are always a number of approaches for defendants to take in resisting them.