The Police Force Of The River Thames River Police patrol boat speeding on the River Thames, with Tower Bridge in the background. The oldest part of London's Metropolitan Police Force, the Thames River Police, was formed in 1798. In 1839, ton years after Sir Robert Peel had formed his police force, the two combined to become the Metropolitan Police as we know it today. The River Police Station at Wapping is built on the site of London's earliest court - the old "Thames Police Court". Although they keep a sharp lookout for wrongdoers, the River Police are more often employed in rendering first aid to drowning people, or helping river workers, than in making arrests. April 10, 1946.