§ Mr. Dalyellasked the Secretary of State for Scotland if he has conveniently available figures for the percentage of water mains in Scotland over 40 years old and which are made of cast iron; and what rough percentage are protected against corrosion, either inside or out.
§ Mr. Allan StewartWater supplies in Scotland are the responsibility of the regional and islands councils. Available records are such that it is not possible to give exact figures, but it is known that only a very small proportion of the older cast iron water mains in Scotland is positively protected against external corrosion. Where this has been done it has generally been to deal with a particular ground corrosion problem which has become evident. However, most cast iron water mains of all ages are protected against internal corrosion where the water supplied is likely to cause deterioration.