Robins at war!

We have had a couple of robins in the garden for a while and I assumed they were a pair however at lunchtime today I spotted them on the fence, and one was chased off (top left), he then came back (top right) and you can just see the other robin, a stand off (bottom left) before the one chased off first flew into the tree (bottom right).

Not great photos as it was grey and they were moving quickly, so I barely had time to grab my camera.