There are many different species of slug in the British countryside. Among the most noticeable are those large Black or Red ones which seem to be slithering about in vast numbers right now. On our walk yesterday, this one caught Malcolm's eye. Considering its size, it would have been difficult to miss it.
Arion ater), or a species all of its own, namely Arion rufus. This specimen was a good 5" long and made an impressive sight. The orange-striped edges of the foot were particularly eye-catching.