Muntjac deer

I encountered a new animal yesterday. There was a tiny deer in the field with the horses, and at first I assumed it was a stray fawn. But it was thick-bodied and obviously not a baby, and Google identified it as a Muntjac deer, also known as a barking deer. They're native to Southeast Asia, but were released to breed here by some idiot and have now made themselves quite at home all over England.

The picture with the horses in the background shows how small it is. (And as a bonus, there's a magpie by the foot of the horse on the right.)