The Watermen (Tom Pascoe #1) by Patrick Easter

'Patrick Easter is a find. A first-rate historical thriller, particularly memorable for its evocation of the Georgian underworld and the crime-ridden Thames. . . it's fortunate for us that there are more to come'
Andrew Taylor

It is 1798 in the Port of London: a cruel villain holds sway over the underworld. His name is Boylin. His face is scarred by lime and his back by the two hundred lashes he received following a naval court martial. He holds Caprain Tom Pascoe responsible for his suffering.

They meet again when Pascoe becomes River Surveyor for the newly formed marine police. They've had orders to investigate a sudden fall in government revenue that is affecting the nation's ability to fight the war against Napoleon and tem the rising tide of Irish rebellion. Pascoe knows that Boylin is behind it, but he can't prove anything - yet.