Via a lovely thread on the BookCrossing website forums, I find on Flickr Trevor Powell's photos of what could be the UK's 67th phone box book swap thing in the sleepy Essex village of Little Bentley.
It was converted into a book swap by Mike Taylor and John Leggett and started operation in August 2011.
Its a traditional four shelf unit, jam-packed with around a hundred books, and also a lively parish noticeboard advertising quiz nights at the nearby Bricklayer's Arms. No sign of any of Dan Brown's works, but The Time Traveller's Wife is represented and also reassuringly General Sir John Hackett's The Third World War.
It looks like the nearest public library is in Greenstead, about 7.2 miles away toward Colchester and there is a mobile library service which serves the village every fortnight.