In relation to Bob's image of an animal dropping I agree with Liz I think its a polecat scat too.
I got the above diagram of mammal droppings from 'google images'
Description of polecat droppings:-
When fresh they are usually black with much fur and small bone fragments and sometimes plant material. They have a very strong 'musty' smell. The droppings have a typical twisted 'mustelid' appearance with tapering ends. They measure 7cm in lenght and 0.5cm in width. There will be no fish remains unlike mink (and otter). Fish bones have never been observed in polecat scat. They regularly use latrines.
Here is a tip which Geoff Lyles the otter expert once told me - If you come across dry otter spraint 'never' take a good sniff of it otherwise you will end up with small fish bones firmly entrenched up your nose which may require a visit to your local 'A&E' department to be removed!
(The above facts were obtained from 'The Handbook of British Mammals' (Blackwell Scientific Publications) and the 'Wild About Britain' website link below