They are by far the most common animals kept as pets in the UK, with 10.2 million dogs and 11.1 million cats. According to the PDSA, 80% of UK dogs and 82% of cats are treated with parasiticides (more commonly known as tick and flea treatments). Dogs and cats therefore represent a large percentage of the total amount of these products used on UK pets.
Banning the five active substances in question from appearing in medicines for dogs and cats could potentially have a significant impact in terms of preventing environmental harms. As mentioned above, there would still be plenty of alternative medicines available.