M25 Travelling Clockwise, by Roy Phippen M25, Grays Essex England

One of the few statistics that Roy Phippen does not provide in his superb virtual tour of the M25 is how many relationships have foundered in cars trapped in its traffic jams with scant hope of a welcome break (there are only three services along its 117 miles).

One of the few statistics that Roy Phippen does not provide in his superb virtual tour of the M25 is how many relationships have foundered in cars trapped in its traffic jams with scant hope of a welcome break (there are only three services along its 117 miles). Fear no more the heat of such moments. With this book in the car, your passenger will be offering enthralling nuggets of knowledge about the countryside through which you are travelling, the road underneath your tyres, the history of buildings seen and (oh bliss!) directions to unsigned, comfort-filled cafés.

Phippen is an unusual guide. A classicist, he dealt in antiquities, taught in primary schools for 12 years, and ran a fashion business with his wife. He finally took to the road as a cabbie, and found that circumnavigating the M25 was a regular feature of his life. Questions from passengers led to research and enough M25 knowledge to fill a book.

The tall tower of the former mental hospital at Shenley (between J22 and J23) is full of police electronics; between J4 and J5 is the artist Samuel Palmer's "Valley of Vision"; the metal wing on a redbrick tower at Chatley Heath, between J9 and J10, is part of a semaphore apparatus that could once send messages between Portsmouth and the Admiralty in 15 minutes.

The idea of an orbital road around London came early: a Royal Commission proposed one in 1905. "I leave the reader to conjure up a vision of this road... full of horses and wagons, supplied with water troughs and patrolled by wheelwrights and farriers to deal with breakdowns," Phippen remarks in the first of the dry asides that give the book its trenchant character. In 1941, four concentric roads were envisaged, the outer not far from the route settled in 1975, when work began in earnest. The finished circle was opened in 1986 by Margaret Thatcher, who enjoyed a swing of her handbag at "those who carped and criticised".

Everyone now (except perhaps the legendary Scot who went round dozens of times in search of his native land) takes the benefits of the road for granted. And tempers will be calmed by Phippen, for his book explains the influence on traffic problems of natural features such as hills and rivers, pressure from powerful local interest and, in the case of those lumbering lorries, failure to keep up the revs.

Just as imaginative as the content of this book is its presentation, a sturdy format with rounded corners and stiff pages. The many full-page photographs are spectacular. Sadly, Phippen died suddenly this year. His legacy is a book that all M25 travellers will treasure.