Sparrowhawks are small birds of prey. They’re adapted for hunting birds in confined spaces like dense woodland, so gardens are ideal hunting grounds for them. The sparrowhawk is the bird of prey you’re most likely to see in your garden. They are sometimes confused with kestrels (which have dark eyes), merlins (which are birds of open country) and goshawks (which are far rarer and very shy).
This was in Dad’s garden and had just killed (probably) a sparrow – it’s quite hard to tell from the remains what it was. He took this photo.