Baker’s Mill Lower Lock is one of those on the canal designed to take craft up to the standard dimensions of Thames barges. It is therefore a little over 90 feet long and about 13 feet wide. It had a rise of 8 feet and was one of the locks shortened in 1840-41 by about 20 feet by throwing an arch across the top end of the lock and resiting the cill and the gates. This was to reduce water consumption and was possible because by this time shorter ‘long’ boats had replaced Thames barges on this section.
The chamber is a mixture of stone and brick lining – the latter probably repairs - and stone quoins, with a substantial stone coping and stone-edged recesses for the gates. There are two sets of recesses at the top end of the lock, one for the original gates and the other the result of the shortening of the lock. Much of the ironwork seems simply to have been reset. There are surviving traces of ironwork associated with the gate hangings.
Despite repairs and patching, and the fact that it is heavily overgrown, the lock chamber is substantially intact.
There is a dam across the top of the lock to hold back water in the concrete lined section above.