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A PHYSICIST WRITES . . .
(February 2006)
Looking back over 35 of these columns, I’m astonished to see that I’ve hardly ever mentioned maps, and then only in passing. The relationship between maps and the real world has always fascinated me. If I study the local map of a place before visiting it, I usually find myself thinking (when I arrive) how well the place matches the map — which is absurd, because the real marvel is how well the map-makers have done their job!
How on earth do they manage to record every ten-metre detail of every feature, as in the 1:25,000 OS maps? When they join one piece of map-making to the next, does it never happen that the two parts of a road don’t quite line up on the page? As for contour lines, if you study these with patience they will give you a clear mental picture of each hill and valley — but how are all the heights measured and the contours plotted? It’s mostly a mystery to me.
Small-scale maps (ie, ones covering a large area) can be just as absorbing. Who could fail to observe the clockwise pattern of the grand old trunk roads out from London: the A1 to Edinburgh, A2 to Dover, A3 to Portsmouth, A4 to Avonmouth, A5 to Holyhead and A6 to Carlisle, with the A7, A8 and A9 similarly arranged around Edinburgh.
These roads were the strands on which a vast spider’s web of road numbering was achieved by the Ministry of Transport in the early 1920s. And have you noticed that within each ‘sector’ between the trunk roads, nearly all the roads have numbers commencing with the same digit? For example, the numbers east of the A1 — all the way up the country — begin with a 1, while those in Kent and round to the A3 start with 2 (the exceptions to the rule are mostly roads that cross from one sector to another, plus some early motorways).
Hence the numbering of the other main roads out of London: the A10 northwards, the A11–13 roads to East Anglia, the A20 across Kent and so on. There are no such radial roads beginning 5 or 6, because the A5 and A1 exited London so close together. As for the A6, this started from the A1 at Barnet and then actually met the A5 in the centre of St Albans. The roads couldn’t cross (though the traffic did, of course) because this would have upset the clockwise numbering! Fifty years ago I was at school nearby, and I well remember the congestion around this junction.
Over the years since the 1920s, some of the radial routes have lengthened (such as the A4, which originally stopped at Bath). Naturally, many have been diverted to avoid city and town centres. And alas, a few have been cruelly dismembered...
Thirty years ago I was living in Harlow, which was bordered by the A11 road to Norwich. Then along came the M11, just beyond. The authorities decided that the best way of persuading traffic to use the new motorway would be to erase the old road. And I mean erase: within Harlow, the A11 road number and even the name of Epping (a few miles south) were painted out on all signs. Before long, forty miles of the A11 had been renumbered, from Woodford up to near Duxford (where the M11 diverges left for Cambridge), in some parts as a lowly B road.
I recall getting quite worked up about this at the time. And I still fume when I glance at a map and notice how a famous old road has been broken up in support of a new one. After the M1 was built, along with its M10 spur just south of St Albans, a fifteen-mile length of the A5 — Roman Watling Street, no less! — suffered ‘demotion by numbers’ (and pity also the A6, which now starts from Luton). And yet, beyond St Albans the A5 was tracked by the M1 for sixty miles but was allowed to keep its identity. Where is the logic in this?
Then there’s the A30 ‘Great South West Road’ from Hounslow all the way to Lands End. This has remained remarkably intact, considering the distance it runs parallel to the upstart M3 and A303. But west of Basingstoke eight miles of the A30 are sadly lacking, having become first the start of the A303 and then a shamefully unclassified road that’s almost invisible on the map. I once succeeded in following this old A30 towards home, though so far I’ve not managed to locate the outward connection while on the move.
But the road which has suffered the greatest indignity is surely the A34. Although this originally went only from Winchester to Oxford, for much of the last century it marked the backbone of England as far as Manchester. Then, with the completion of the M40, fifty miles of the A34 were cut out between Oxford and Birmingham — or rather, it was renumbered in two sections: A44 and A3400.
And here are the final absurdities: in the great radial pattern of trunk roads the new A3400 sits midway between the A4 and A5. So if the carve-up had to be done at all, this leg ought to have been given a number beginning with 4! As for the now isolated stretch of the A34 through Birmingham and up to Manchester, plainly it too should have received its own number, starting with either 4 or 5. The road-map of England doesn’t always delight the mathematician and the map-lover in me...
Peter Soul
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