Beware Spoiler Massive plot hole. Solving the crime hinged on finding the master tattooist but when this artist was found it turned out that he merely erased the tattoo. Also, the chance overheard conversation in the police canteen seemed very contrived and Wilfred Bramble's 'mad professor' performance was - let's just say - Inappropriate. Oh, and Duggan continued to pile up huge travelling expenses! Atmospheric, I admit, but there are many better episodes.