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.

If you, like me, are sometimes intrigued by place names in Britain, their often eccentric spelling and counterintuitive pronunciations, you may have tried to research their origins and history, whether in books or online.

Sites such as Wikipedia and those of local history groups often provide answers to your questions but quite often such a search proves fruitless. In any case, it is good to have a reliable starting point.

By “reliable”, I mean a source that can be trusted to be accurate. Too often, the “etymologies” you find online are highly misleading when not completely fictitious. One should always check multiple sources but even this is no guarantee as online contributors are notorious for copying one another without bothering to check whether what they are copying is correct.

My favourite starting point in searching for the etymology of a place name is A Dictionary of British Place Names by A.D. Mills (ISBN 9780199609086).

This modestly-sized paperback contains a surprisingly large number of names (over 17,000 according to the blurb on the back).

Names are arranged alphabetically, as you would expect. The individual entries are expressed in a terse note-style language but the meaning is always clear. Where the derivation is known, the original words in Anglo-Saxon, ancient British dialects, Norse, etc. are given together with their meanings. Where a name has evolved through several versions, these are given, referred to the written source (e.g. Domesday Book) where they are found.

Discovering what a place name meant in the language of those who first named it can give fascinating insights into the history of the place and its importance to the people who lived there. This book is a valuable guide to this discovery.