The urban and suburban fox population has certainly become more visible, no doubt due to better education and less superstition about the animal and to its ever increasing popularity.

However your article (Times Group, January 4) is incorrect in suggesting fox numbers have increased.

London's fox population has remained broadly stable for 25 years and our observations actually suggest a decrease of up to 20 per cent over the past four years.

As part of a nationwide network of wildlife hospitals, I can assure readers no increase in hepatitis, or any other disease, has been noted in foxes.

Therefore, there can be no justification for blaming foxes for any increase in the disease within the dog population.

As regards mange, which affects all canines dogs and foxes alike the current increase in the spread of this parasite is down to global warming, not to foxes.

As your vet suggests, vaccination largely wiped out hepatitis in dogs many years ago.

The same applies to distemper and parvo virus.

Wild animals are naturally more healthy and disease resistant than domestic animals.

Far from being a threat, wild animals have always been more at risk from their less healthy cousins than vice-versa.

Trevor Williams

Director, The Fox Project, Kent