Flea collars banned in France over suspected human health risks are still being bought by thousands of British pet owners.

The collars were removed from French shops last month after experts decided the danger – particularly to children – was too great. Among the collars withdrawn are those containing dimpylate, also known as diazinon.

It is an organophosphate originally developed as a nerve gas during the Second World War.

Last night there were calls for Britain to follow suit and ban the collars for cats and dogs.