The force policed 33,000 workers in the river trades, of whom Colquhoun claimed 11,000 were known criminals and "on the game". The river police first received a hostile reception by those dockyard and wharf workers not wishing to lose an illicit income. A mob of 2,000 attempted to burn down the police office with the police inside. The skirmish that followed resulted in the first line of duty death for the new force with the killing of Gabriel Franks. Nevertheless, Colquhoun reported to his backers that his force was a success after its first year, and his men had "established their worth by saving £122,000 worth of cargo and by the rescuing of several lives."