The first pair of locks as you come off the Thames at Brentford are Thames Locks, which separate the fully-tidal section of Brentford Creek from the semi-tidal section up to the Gauging Lock. At high tide, as here, one can pass through the locks with all gates open. The locks are keeper-operated and only worked for a window either side of high tide, when this falls within BW working hours.
This picture was taken in 1978 when we returning in the original Felis Catus from a cruise to the Kennet & Avon.