TOP LOCK AT TQ 3675 8398

The Top Lock on the Hertford Union Canal, built around 1830 with 20th-century alterations, is a lock structure made of brick with stone and brick coping. It features two sets of double wooden gates, with the top gates equipped with steel balance beams and the bottom gates having rare cast iron balance beams. The lock includes ground paddle gearing at the top and gate paddle gearing at the bottom. The wing walls are constructed from brick, with stone and concrete coping. Additionally, there are brick heel grips and brick-paved lockside surfaces. The Hertford Union Canal connects the Regent's Canal with the River Lea Navigation and was opened in 1830.