Out walking along a canal towpath, I just saw this, on the far side of the canal. Looked away and something in my head said, look again. I did, but it was a long way away. Only had a shortish lens on my camera, so took a photograph and magnified it on the back of the camera. I was quite surprised my initial idea was correct. It is a non native Terrapin, probably an ex pet, illegally released when it got too big to look after. It looks tiny here but was probably a minimum of twelve inches in length.
