Oh the drama! Who needs TV?!!
I had something similar a few years ago, a commotion in the back garden, looked out the kitchen window and saw the sparrowhawk had caught, and was struggling with, a (large) pigeon!
As I was watching, thinking, well, Pigeon is dinner, the little black cat who "lives" in my garden ran out from nowhere and attacked the sparrowhawk! I ran outside to intervene, and Sparrowhawk flew off, Cat ran away, and I was left with a very injured, very sorry looking pigeon.
After a bit of a chase, it wedged itself nearly under the fence, and I had to haul the poor thing out and hold it until I could put it way up high in one of my hedges. I knew Cat would return. Pigeon did not like the hedge, and kept flopping down to the ground. Eventually, it disappeared under the hedge, and I'm sorry to say, I never did see Pigeon again.