At the age of 58, he has just put Paris on the map and, especially, its Mtro. With the exception of just a couple of illustrations, he carried out every process in The Paris Mapguide (Penguin, £4.99), from pounding the Parisian streets for research to setting the type. The darkroom of his home used to be the downstairs loo. His typesetting machine and lightbox are now in the bedroom of a daughter who has conveniently moved out. "It's a very slow process to produce a map," he says. Particularly if you do everything yourself.
"Mapguides" is a term thought up by Joan, his wife. While his Penguin map of Europe is just that, ditto of Europe and North America, his mapguide of central London is a slim guidebook with 30 pages of maps or, alternatively, a 30-page, six-inches-to-the-mile street directory plus pubs, statues and opening times of the Trafalgar Square Post Office. The Paris Mapguide is fatter, covering most of the area inside the Priphrique ring road. Streets, domes and temples lie, open to Middleditch's eagle eye. "A triumph of clarity and design," declared the judges who gave it a cartographical award.
Yet the most spectacular piece of mapmaking is of terrain visible to no one. The Mapguide opens with a new design: Middleditch's Mtro. This is reminiscent of the London Underground map but more realistic.
The London Tube map is a classic of design, a highly effective piece of fiction. It is a triumph of geometry over actuality, all straight lines and clean bends. So that the mind can grasp it, the wobbles have been ironed out. Liberties are taken with the points of the compass: Chancery Lane, for example, is not due east of Notting Hill Gate but north-east.
"I've tried to give the Mtro map its own character rather than make it just a London Underground map with different railway lines." His task was made more fiddly by the virtues of the Mtro itself: "Twice as many lines as London's Tube and more than twice as many stations." He has even included the "Mtor" line, No 14, from St Lazare in the north-west to Maison Blanche in the south-east; it doesn't open until 1997.
"I've also tried to keep it both geographical and geometric, a compromise between the two. I play around with the lines until it looks attractive and reads well."
One compromise is with Line No 1, which runs right across the map from Dfense in the west to Vincennes in the east. This is Paris's answer to the Central Line; coloured in a similar crimson hue, it too is drawn for most of its length along a dead level east-west axis. This is the core of the whole design. Yet it is an idealised version, as just one stop, going west from Concorde to Champs Elyses, demonstrates. The street map reveals that the stretch of track in fact tilts down on the right- hand end.
The street map itself is a slight variation on reality. All maps are. "Everything is exaggerated; you have to make a road wider to get its name in." He was continually drawing and redrawing.
Michael Middleditch was 17 when he first went to Paris with his grandmother: after many visits the city still offers its rewards. He remembers walking around as a teenager with his mind full of Leslie Caron in An American in Paris: "Nearly 40 years later, during the making of this mapguide, I stood next to her in a shop in rue de Rennes." Given all this time spent prowling about the place, what's his French like? "Every time I use it," he answers, "they reply in English."
Michael and Joan Middleditch took to the Parisian pavements for a solid five months. They noted and photographed everything, down to statues and murals. They stumbled across two Statues of Liberty and one flame all by itself. They rode on the buses to check the routes.
The completed masterpiece includes not just the big-name restaurants but also the smaller establishments whose cuisine the two of them have enjoyed. As well as tourist traps like the Folies Bergres, it marks the small jazz clubs where they have tapped their feet."If you do it yourself," Michael says, "you can indulge yourself and include your own interests."
Once all the information has been gathered in, he takes, as do all cartographers, a standard "base map" of the city and then imposes his own design on it. "I start with the outlines, all drawn by hand, and I hand-letter the words. Then I typeset the street names and stick them over the top." Instead of the customary four colours, he uses six to mark out the different features.
Michael Middleditch returned to France for a final check on accuracy, only to discover he had to take account of a complete change in the colour coding at the Louvre. Actually, the museum should by rights have followed Monsieur Middleditch instead of the other way round. But that, of course, would be a clear case of putting the cartographer before the horse.