Question to the Department for Work and Pensions:

To ask Her Majesty's Government whether the annual treatment of the River Stour in Dorset to prevent infestations of the Blandford Fly is effective; and what is their assessment of the risks of that treatment, if any, to (1) human, (2) animal, and (3) plant life.

Local monitoring by General Practitioners of the incidence of bites in the 1990s showed a decline. Whether this was due to the annual treatments cannot be proved conclusively.

Dorset Council is undertaking a trial into the effectiveness of a biocidal product against the Blandford Fly. The Health and Safety Executive’s assessment of the product in question, conducted as part of providing an authorisation for its use, concluded that the risks for humans, non-target animals and the wider environment were acceptable.