Sir - The remarkable news recently has not been so much that sophisticated DNA tests have proved the presence of poison-resistant rats in Oxford, but that Jean Fooks has denied this both to your reporter (Report, April 4) and in writing.

It is scarcely consistent with a liberal or democratic tradition to deny reputable scientific evidence, least of all in a city like Oxford, so renowned for its researches into the life sciences.

While not being dictated to by scientists, the politicians of other parties would, I think, be rational enough to allow their policies to be properly guided by scientific evidence of the problems facing us.

Roger Moreton, Oxford