Reference:
Whilst we would not suggest that foxes will never kill cats what we can say is there has never been a reported case of this happening. Usually foxes and cats have a mutual respect for one another. The time of year when calls peak are usually around March / April / May. People will view a fox chasing a cat and wrongfully assume that the fox is looking to kill the cat to feed her cubs. What is happening however that whilst cubs are still very young and underground cats will show a very unhealthy interest in them. If the cat was to get to the young cubs it would kill them. A vixen looking after her cubs will chase cats away from the earth. Calls again then peak usually around July where householders are claiming that a pack of foxes is going around terrorising cats. Since foxes do not hunt in packs we can assume its a family of cubs learning their way around their territory. On discovering a cat they tease the cat, in the countryside the badger is usually the one that the foxes will tease, one would never believe that the young cubs were looking to kill the badger! Once the cubs have met with the ferocity of a cat they learn quickly to avoid them. If a fox finds a dead cat on the road it will take it away to eat. Any person observing this will assume that the fox has killed the cat. We have observed on many occasions foxes carrying marrow bones, never do we conclude the fox has killed the cow! If more than one fox is present when this cat has been discovered, and since foxes are so selfish with their food, an argument over who's it is will commence. Remembering on many occasions that the police have been called out thinking someone's being attacked and killed because the foxes are so vocal, it is easy to assume that the foxes are killing the cat since that's what it sounds like.