Fortunately the rending sound was Velcro which had been ingeniously attached to hold the four sections together. The edges were rapidly rejoined and the whole creation was later returned to the wall of the Thirsk public library for which it was designed.
It is the most spectacular of the hundreds of community maps to which Sue Clifford has been, if not the mother, at least a midwife. From the environmental charity Common Ground, she has given rise to an enormous scheme of communal cartography, the Parish Maps Project. Launched in 1987, the scheme had within two years spawned more than a thousand draw-it-yourself groups.
It is not necessarily the precise borders of the parish she recommends people record but their neck of the woods, their back yard. Get it down on paper (or, as in Thirsk, on fabric) before it disappears under a hypermarket. What developers like is a so-called "green-field" site in the middle of nowhere.
"But nowhere is nowhere," Sue Clifford argues fiercely. "Every little patch has people who know it. Most maps are presented to us as objective ways of telling the truth but they all lie to a degree. Maps are in a sense about power; you can tell who's drawn them." Ordnance Survey gives the game away by its very name; it means "cannon" or" military supplies" and its cartographers clearly saw terrain in the first instance as a place for soldiers to march over and defend. "Our attitude at Common Ground was: let's look at cartography another way. Local people can show what is important to them."
The Thirsk map is constructed entirely of fabric, from brown corduroy for the ploughed fields to tiny patches of cloth on the multi-coloured border. A little money was raised for a professional textile designer to start it off, after which hundreds of people had themselves literally in stiches: petit point, blackwork and pull through.
At 1,536 stitches to the mile, it depicts in lively detail not just the town of Thirsk but also the neighbouring parishes of Sowerby, Norby, South Kilvington and Carlton Miniott. Linking them all is the strong blue line of the river, the Cod Beck. Another element is that it progresses through the four seasons, from spring on the left to winter (with the inevitable robin) on the far right.
"It isn't passive," Sue Clifford says. "Placed in a public position, it keeps people talking. And conventional maps sacrifice an awful lot of local detail." She points to the figure of a man in cricket whites: "That is Thomas Lord, after whom Lord's cricket ground was named; he was born locally." Then she indicates a tiny image of a tree: "There is now a beech here. On this site there was an elm on which, so the story goes, the Earl of Mowbray was lynched for speaking up for the poll tax." We are going back to pre-Thatcher days, of course.
For its forthcoming series of exhibitions on parish maps, Common Ground (44 Earlham Street, London WC2H 9LA) would like to hear from any local groups that have produced one.
As for the Thirsk inquiry, the jury, or rather the inspector, is still out. But if the pylons are to be dumped on the horizon, at least they will be sufficiently far away for the local cartographers to be spared the trouble of adjusting their map.