At the original trial, the judge had found the plaintiffs to be genuine complainants whose lives had been affected by the disturbance. But in determining whether environmental interferences are sufficient to amount to a nuisance in law, the courts have long held that there is no right to absolute quiet, and that it is necessary to take into account both the nature of the locality and the level of disturbance which it can be considered reasonable to put up with, whatever the actual effects suffered by the plaintiffs.
In the present case, noise level readings had been taken by experts for both parties. Reference was also made to a 1980 document published by the World Health Organization in its Environmental Health Criteria series which said: "Studies have indicated that the disturbance of sleep becomes increasingly apparent as ambient noise levels exceed about 35dBA."
The trial judge had concluded that the measured noise levels at night were the same as or marginally above the WHO recommended levels. Nevertheless, after taking into account the paucity of complaints from other neighbours and the proximity of the Ilminster by-pass, he decided that the noise was not sufficient to amount to a nuisance.
On appeal, counsel for the plaintiffs argued that the judge had failed to understand fully the WHO report, and had failed to appreciate its emphasis on the importance of undisturbed sleep. But the Court of Appeal upheld the finding of the trial judge.
According to Lord Justice Pill, who last year was appointed to take on a special watching brief on environmental law in the Court of Appeal, sleep was a matter of importance but there was no proposition in law that there was a common law nuisance if sleep was disturbed in a house in a locality such as that in the present case. The trial judge was entitled to take into account other factors and to decide that there had been no nuisance in law.
Traditionally, the courts have drawn a distinction between nuisances which cause physical damage or personal injury, and those such as smell which cause a general interference with the quality of enjoyment. In the latter type of case the nature of the locality has always been taken into account, while in cases where physical damage has been caused the courts have taken a tougher line ignoring locality considerations. With increasing scientific evidence that noise disturbance may cause genuine physiological injury, it may be that in future this line will not be so easy to draw.
Nevertheless, at present quantitative standards, such as WHO guidelines or those in the British Standard BS4142 concerning industrial noise affecting mixed residential and industrial areas, are of more use in predicting likely complaints than in providing clear cut-off points for a nuisance in law. The situation may, however, change.
In 1996, the European Commission published a Green Paper on noise policy which noted that several Member States had incorporated WHO guidelines into their national noise legislation. It called for EC harmonisation of the assessment of noise exposures, and tentatively floated the idea of introducing common exposure targets at a later stage (ENDS Report 262, pp 40-41 ). Proposals stemming from the Green Paper are awaited - but binding EC standards in this field may run up against the wall of the subsidiarity doctrine.