What bird is this?

We went for a picnic, and played ball and did quiz questions in the sun today.

There were loads of these birds around. They’re about the size of a thin blackbird, Brown feathers with a lighter front. They were hopping (more like jumping) along in short sharp bursts looking, successfully, for worms.

There was one that was minding its own business, when a gull flew over it, and deliberately slowed and swooped to scare it off.