London Borough of Wandsworth (click on photographs to bring up bigger/better versions).

Click here to
see pic I've
taken from www.geograph.'s site.
This one at Tooting, although described as a pump, has been modified over the ages and there's not much left resembling a pump.

Markings: A date "1823" and the inscription "ERECTED BY THE PRINCIPAL INHABITANTS OF THIS PARISH". There's also a modern plaque in front of the pump but it's indecipherable in the photo.

Manufacturer: Unk.