asked the Secretary of State for Northern Ireland how many clay land drainage pipes were used for agricultural land drainage in Northern Ireland in each of the last three years; and what percentage this was of the total length of land drainage carried out in Northern Ireland in each year.
This information is not available. However, it is estimated that in Northern Ireland some 8 million-10 million ft. of agricultural field drains have been laid annually in recent years and that the percentage of clayware pipes fell from about 20 per cent. in 1971–72 to less than 10 per cent. in 1973–74. A survey of claims for field drainage grants since December 1974 suggests that clay-ware pipes now account for only about 4 per cent. of the field drainage pipes used in Northern Ireland.