Claremont Square leads off Pentonville Road at its highest point, a short distance west from the Angel, Islington. London’s Georgian squares typically comprise four rows of houses forming a rectangle enclosing a park or garden in the centre. Claremont Square encloses, not a garden, but a reservoir.
The first reservoir was constructed in 1709 and was open to the sky. It was placed at this point so that it could provide water to the surrounding district which lies at a lower level.
The above photo shows a partial view of the present reservoir. This one is covered over and was built to replace the open pond in 1855-6.
The water for the reservoir was originally supplied by pumping it up from the New River Head. This was the terminus of Sir Hugh Myddelton’s New River which opened in 1613 to bring water from Hertfordshire to an increasingly thirsty London.
The New River still exists though much of it has been covered over as the urban area spread around, and sometimes over, it.
These days, the reservoir is supplied from the Thames Water Ring Main. There is an access point for this down the hill at the New River Head where some of the old buildings still exist in what has been designated a conservation area.
As you can perhaps see, the reservoir is surrounded by railings preventing public access. This means that this small area serves an important secondary function as an urban wildlife refuge. Birds and squirrels can go about their business unmolested and I once saw a fox atop the hump.
It is curious how few people are even aware that there is a reservoir here.