A few weeks ago Keith and I went down to Chatham Docks to see the Great Northern Diver that is wintering there. On that occasion we were unlucky but Keith returned on New Years Day and got this wonderful picture.
Great Northern Diver
Birds and trains and history and all of the things that I enjoy
Pete's Favourite Things 
If I was a GND I think I’d starve – is it really going to get that crab down it’s neck? 😉
It does seem an odd food source I agree Stephen. I tried again yesterday (and failed again) to see the bird, but talking to Keith and the other local birders it does seem to have developed a liking for the crabs in the dock basin. I presume it must have mastered the knack of cracking the shells against something hard (? basin wall) and then extracting the the insides from the broken shell.