Three Mills Lock, also known as the Prescott Lock is a lock on the Prescott Channel on the River Lea in London. The project was led by British Waterways and the lock officially opened on 5 June 2009. The lock cuts off this section of the Bow Back Rivers from the tide, creating new opportunities for leisure boats, water taxis, trip boats and floating restaurants. It also helps freight traffic such as barges carrying construction materials to the sites of the 2012 Olympics and Stratford City.