intriguedDidn't seem to have any white on it and it looked a bit big for a stoat (definitely too big for a weasel), and googleing doesn't suggest any local colonies of feral ferrets, so I'm thinking probably mink? Though it wasn't near water (maybe a couple of miles from the River Tamar), it was on the side of a hill with lots of gorse and rabbits, so plenty to eat and plenty of cover.
*though I've always thought that searching the whole of Devon and Cornwall for something the size of a polecat to check it's not there would be one hell of a job.
