Aynho Weir Lock

This is Aynho Weir Lock on the Southern Oxford Canal, south of Banbury. The lock is a curious shape, with narrow gates at each end, but with a chamber that widens out to around 20 feet, making it awkward for solo boaters with shorter boats, especially as there are no bollards to tie onto (or, at least, there weren't when the photo was taken).
The lock only has a fall of around 1 foot, but it feeds the 12 foot deep Somerton Lock, 3 miles downstream. So, the unusual shape is to allow extra water to be sent downstream each time the lock is used.The River Cherwell crosses the canal on a level just above Aynho Weir Lock, sometimes creating interesting currents.
See Google Aerial View of this location.