The castle was an amusing solution to the problem of how to house three massive steam engines attractively.

It was built in 1856 after a cholera epidemic 10 years earlier. A law was passed saying all water had to be filtered before it could be drunk.

The enormous turreted building was created to lift water from nearby filter beds in Green Lanes and pump it at street level to the rest of London.

Well-to-do residents wanted to make sure the building was in keeping with local properties. William Chadwell Mylne, the engineer and architect, came up with the idea of building a castle, integrating parts of the exterior design into the pumping operation. The monogrammed flying buttresses which jut out on the west-facing wall were for the fly wheels; the smaller tower with a square top was a reservoir; and the tallest tower was a chimney for the boiler house.

It is commonly believed the design was based on Stirling Castle, mainly because Mylne's family was of Scottish origin. The base of the building is in heavy, stocky baronial castle style, but the three incongruous turrets are reminiscent of Italianate towers.

The pumping station sits on New River, a 38-mile aqueduct built between 1609 and 1613 to bring fresh water from Ware in Hertfordshire. Originally the water supplied only 1,000 customers - most people were dubious of water arriving by wooden pipe from miles away and preferred water drawn from local wells, even if it was contaminated.

The open canal is visible in parts of Islington and Haringey and still supplies some of London's water.

But since an electric pump was installed at the castle site in 1942, the old pumping station has been idle. Plans for it to be turned into an art gallery or museum were never

considered cost-effective.

(Photograph omitted)