As an operations engineer with over 25 years' experience, I would refute the claim in your news article (NCE 6 September) that sewer leaks are often directly linked with maintenance procedures.
The article suggests poor repair works can create weak spots which can be exploited by rats. But having worked on a nationwide project for over a year examining rats in sewers, the statement is most certainly debatable and was not an aspect highlighted in the UK wide responses to the study in which I was involved.
Our conclusions differ from those of Stephen Battersby, who is mentioned in the report and has previously written reports on rats in sewers.
However, our underlying message was that the water industry should not adopt a complacent attitude to rodents in sewer networks.
Neil Watson (M), 2 Glenisla View, Meethill Road, Alyth, Blairgowrie, PH11 8DE