The current thread on the A12 reminded me of this.

When I was young, it always struck me as rather strange that the trunk road from London to Norwich struck out boldly across relatively unpopulated country, rather than following what would seem the obvious route via the A12 and A140 through Chelmsford, Colchester and Ipswich, which is also followed by the main-line railway.

The A303 and A5 through the Midlands, for different reasons, follow similar courses. Are there any other examples of historic routes that do the same?

If we're talking major population centres then the A1 could be included. between London and Newcastle you've got only got a few larger settlements - Doncaster for example.

Ian (M5 DRIVER)

True now, but bear in mind that the A1 used to plough through the centre of quite a lot of medium sized towns - Barnet, Hatfield, Welwyn, Stevenage, only just missing Peterborough, Stamford, Grantham, Newark and Retford before Doncaster. No huge places, but quite a lot of people in those towns all taken together. There's then a long gap before Darlington where the only settlements are small ones, but really the A1 took the obvious way to Edinburgh, it just didn't need to go through, say, Leeds just because it was only a few miles off the straight line.

I'm going to disagree with you here: the A12 picks up larger settlements, but there's nothing of any size on the A140 at all unless you make the detour into Diss. The A11 has a much more regular pattern of towns (Epping, Stortford, Saffron Walden, Newmarket, Mildenhall, Thetford, Attleborough and Wyndham) so makes a lot more sense for a coaching route and early motoring route to Norwich.

The fact the main railway goes that way is largely historical accident: rivals tried to build a western route via Newmarket or Cambridge, but got bogged down in politics. Even on what we ended up with, you could run a reasonable service via Ely, and I think pre-unification there was one.

hardly just missing, ploughing through the centre of all those, other than Peterborough.

Missed Northallerton though (post-24).

The most obvious is arguably the A5, which conspicuously manages to avoid the entire Coventry-Brum-Black Country conurbation.

Yes, sorry, "only just missing" was just meant to refer to Peterborough. My clumsiness.

How about the M6 'avoiding' Manchester in a similar way to the A1 and the East Mids and Yorks places or A5 and the Cov-Bir-Bla-Wol agglomeration.

This being because they chose Watling Street over Telford's coach route to Holyhead from Weedon onwards for the route of that number.

Not sure that that's quite the same. Our long-distance motorways always skirt the major conurbations, except where they're the final destinations.

Not really - OK, the M1 passing between Nottingham and Derby is similar, but the rest make an effort, via a divert, to serve the larger towns/cities more directly.

But the M6 closely follows the historic road route through Newcastle, Warrington and Preston, and also the route of the West Coast Main Line.

Between Doncaster & Darlington the main historic route was York, Thirsk, Northallerton (A19/A167)
Also Stevenage & much of Hatfield are New Towns, so are post A1

The A11 goes through Thetford, which used to be a very important place in times gone by and of course Newmarket with its racing tradition.

Derek

And the A1 takes the Great North Road and the A5 Watling Street