Christopher Fowler 
Bryant and May On The Loose 
(Bryant & May Book 7)

Long regarded an anachronism and a thorn in the side of its superiors, the Peculiar Crimes Unit is to be disbanded. For octogenarian detectives Arthur Bryant and John May, it seems retirement is now the only option. But then a headless body is found in a freezer, and on the perimeter of a massive construction site near King“s Cross, a gigantic figure has been spotted – dressed in deerskin and sporting antlers made of knives and suddenly, with limited resources and very little time, the PCU are back in business…