asked the Secretary of State for the Environment what is his estimate of the number of people currently employed in research and development in matters of pollution control.

The total numbers employed in the public and private sectors on research and development in matters of pollution control cannot readily be estimated. There are 20 professional staff currently employed on such matters at the Department's Building Research Station and Hydraulics Research Station, but the major part of the Department's programme in this area is carried out under extra-mural contract.