Why does the M6 turn into the M74 in Scotland?

[wrinkly]

No simple account of this stuff can cover all the facts. There are exceptions, counterexamples and anomalies everywhere. There were changes of plan and probably internal fights within the then Scottish Office. The DfT and HE (then HA) were weak - they should at minimum have pressed for the number M6 to continue the few extra yards to the A75 divergence, which is at the border, so that traffic between England, Dumfries and Stranraer would not have touched the A74(M). (If I remember correctly, traffic joining from the A75 still does not pass any sign telling it that it is approaching, joining or on the A74(M).)

The number changes from M6 to A74(M) at the J45 divergence; legal responsibility changes at the border; I'm not sure which of these two places is the changeover point for practical maintenance. Probably at the border, because of the DBFO contract. The kilometre posts count from London as far as Johnstonebridge (J16), 40km north of the border. The number changes to M74 at J13, and the standard changes to D2M where phase 3 meets phase 2 at J12.

[Gareth]

The kilometre posts still count up well into Scotland? Didn't appreciate it was such a mess.

[wrinkly]

The kilometre posts still count up well into Scotland? Didn't appreciate it was such a mess.

If I remember correctly, when the first southerly section of the A74(M) (Kirkpatrick Fleming to Guards Mill) was first built, it initially had kilometre posts numbered from its south end at Guards Mill (what is now J45). It probably had no junction numbers then but I'm not sure on that point. Later, other southerly sections further north had kilometre posts numbered from London. The anomalous section was changed as completion from Glasgow to Guards Mill was approaching, circa 1998-9.

Sadly, I can't remember at what date junction numbers first appeared on a southerly section. Probably when Lockerbie was re-bypassed.


M74 and A74(M) History

[Ritchie333]

I suppose the basic question is, why when all-purpose roads were initially numbered (1920 ?) did the A1 get numbered right over the border and all the way to Edinburgh, but the A6 did not get comparably numbered through to Glasgow.

As documented in the file MT 39/246, mentioned by Steven, in 1934 the Scottish Ministry of Transport asked the MOT if it would be a good idea to renumber the A74 and A82 (which originally met at a crossroads with the A8 in Glasgow City Centre) so the A6 would end in Inverness. The MOT said no.

[IAN]

I didn't say it was a good idea in this case, just that it fits exactly the original methodology that fell into general disuse in the mid-1970s. See the A48(M) Morriston Bypass and the A8(M) Renfrew Bypass (although both opened with the full motorway number) for other examples of this type where both M4 and M8 existed elsewhere at the time.

I could never see the logic of using A48(M) for the Morriston Bypass and then opening another isolated section further west (J44-46) as the M4

[M4Simon]

I didn't say it was a good idea in this case, just that it fits exactly the original methodology that fell into general disuse in the mid-1970s. See the A48(M) Morriston Bypass and the A8(M) Renfrew Bypass (although both opened with the full motorway number) for other examples of this type where both M4 and M8 existed elsewhere at the time.

I could never see the logic of using A48(M) for the Morriston Bypass and then opening another isolated section further west (J44-46) as the M4

J44-46 is the Morriston bypass. You're thinking of the older A48(M) Port Talbot bypass, now J39 to the end of the J41 spur at Baglan.

Simon

[Glenn A]

Also with regard to 7-9 being exclusive to Scotland, almost true, but there is a short section of the A7 in England and the A74 started in Carlisle until 2008. Zone 1 has a small section to the east of the A1 in Scotland, and zone 6 roads are common in the Borders.

[Vierwielen]

The kilometre posts still count up well into Scotland? Didn't appreciate it was such a mess.

It isn't just the M74/A74(M) that is a mess. The A3 has a similar mess. I have identified three sets of kilometre markers on what is not a very long piece of road. Firstly, there are kilometre distances stenciled onto bridges and the like. They appear to have a point near London Bridge as their origin (probably the junction of King William Street and Cannon Street). The second which appears on location marker posts is on the section that passed through the Hindhead tunnel. That sequence has its origin at the Surrey border, close to the Hook underpass and increases travelling out of London. The third sequence which also appears on location marker posts has its origin where the A3(M) joins the M27 and increases as one travels towards London. When the Hindhead Tunnel was built, it used the sequence travelling out of London and the sequence changes where the new road leading to the Hindhead Tunnel meets the existing road.

I won't mention the A1(M) location markers - describing that is probably worth a PhD.

[Nwallace]

It’s a rather long and complex tale so here’s a brief overview. The A74 Glasgow Carlisle road was upgraded to a dual carriageway in the 1950s and 1960s. This was completed in May 1973 with Gretna Bypass opening. The M6 from England simply connected into it (mid 1960s).

Through the 1970s there was calls for the Glasgow section of M74 to be extended all the way to the M6 at Carlisle. An extension did occur in 1986/87 taking the M74 to J12. In 1987 the decision was taken to overhaul the A74 dual carriageway to full Motorway, mostly due to its age and increasing traffic flows. This was built rather quickly from J12 to Gretna Green where it stopped short of M6 J44 by several miles (See Cumberland Gap for more).

The issue of Numbering goes back to the 1920s/1930s road renumbering where England was Given Numbers 1-6 and Scotland Given 7-9.
The M6 was a Bypass of the A6 Trunk road so it was called M6.
The Glasgow M74 was a Bypass Of the A74 so it was called M74. The A74(M) issue was basically a temporary Number while the Motorway was being built in the 1990s. It was interned the M6 WOULD extend all the way to J14, where the M74 goes to Glasgow and A702 Meanders it’s way towards Edinburgh. This was intended to be bypassed by a Motorway (M702??) but these plans were shelved in the late 1990s.

Why it’s not been extended or changed since then is that there is very little interest in changing route numbers and theses plans of the M6 Scotland extension have been dropped and never picked up again....

Actually, the M6 stopped north of Carlisle and there was the ghastly A74 dual-carriageway connecting M6 and M74. This is called the "Cumberland Gap" in the Wiki entry for the M6, and wasn't replaced until 2008

I suppose the Scottish government are looking for a site for a border post now. (only joking) !

It is the only major border crossing that doesn't have the space to build them.
The A1 and A68 have parking areas that could be repurposed.
The A7 well just as in Gretna the toll House is still there (and there is fields to cpo)

Sent from my BKL-L09 using Tapatalk

[Scratchwood]

Leaving aside Motorway numbering, presumably because of the road zoning rules, we have the curio that the A6 only goes to Carlisle, when the A1 crosses the border into Edinburgh?

Otherwise it would have made more sense to have the A6 follow the A74 route to Glasgow to give 2 continuous roads from London to Scotland, one to Edinburgh and one to Glasgow, even if it would be out of zone. Then any upgrades on the Scottish side would have become M6 or A6(M) anyway

[KeithW]

Leaving aside Motorway numbering, presumably because of the road zoning rules, we have the curio that the A6 only goes to Carlisle, when the A1 crosses the border into Edinburgh?

Otherwise it would have made more sense to have the A6 follow the A74 route to Glasgow to give 2 continuous roads from London to Scotland, one to Edinburgh and one to Glasgow, even if it would be out of zone. Then any upgrades on the Scottish side would have become M6 or A6(M) anyway

Before the A1 got a number it was the Great North Road between the capital cities of London and Edinburgh. The A6 was a not a single route in the same way as it meandered across the Midlands. I doubt many drivers drove from London to Glasgow that way. I would have been heading up either the A5/A34 towards Manchester or the A1/A66 to Penrith. In the 1930's there was a proposal to extend the A6 to Inverness via the A7 to Kingstown, the A74 into Glasgow, then along the A82 to to Inverness. The problem was the A74 was not a great road especially at the northern end.

[Micro The Maniac]

we have the curio that the A6 only goes to Carlisle, when the A1 crosses the border into Edinburgh?

A6 = London to Carlisle
A7 = Carlisle to Edinburgh
A74 = Carlisle to Glasgow (spurring off the A7)

IMHO, for consistency, it would have made sense for the A7 to have beeb an extension of the A6 (through to Edinburgh) and then the A7 routing to Glasgow... but that stuffs the zoning in Scotland

But it really makes no sense for the continuous Felixstowe to Glasgow road to have so many identities...

[Ruperts Trooper]

London and Edinburgh were the two hub cities in the 1922 zoning justifying a single route number joining them. Of course, if the 1922 zoning had used London as a single hub for the UK it would likely used a single route from London-Glasgow but that's conjecture.

[KeithW]

A6 = London to Carlisle
A7 = Carlisle to Edinburgh
A74 = Carlisle to Glasgow (spurring off the A7)

IMHO, for consistency, it would have made sense for the A7 to have beeb an extension of the A6 (through to Edinburgh) and then the A7 routing to Glasgow... but that stuffs the zoning in Scotland

But it really makes no sense for the continuous Felixstowe to Glasgow road to have so many identities...

That is the way it actually is. The A6 ends in Carlisle at the end of Botchergate close to the castle. From there you follow the sign for the A7 and the road takes you over the Eden and on to Edinburgh, the A74 branched off the A7 at Kingstown.
https://www.google.co.uk/maps/@54.89176 ... 8192?hl=en

[M4Simon]

But it really makes no sense for the continuous Felixstowe to Glasgow road to have so many identities...

It's a legacy thing. In 1922, Felixtowe wasn't a major port, as far as I know, and there was barely a case for a single road number from Felixstowe to anywhere west of Ipswich. It now has a single route number into the heart of the motorway network (A14). The illogical thing now is the three different motorway numbers, and actually the only one that really shouldn't be there is the A74(M). But as this discussion explains, it has arisen out of changing plans over many decades.

Simon

[Duncan macknight]

The M6 was a Bypass of the A6 Trunk road so it was called M6.

This isn't the case at all. Motorway numbering in England and Wales doesn't work this way - it's only true (mostly) in Scotland.

Oh Cripes, only noticed this now!

[wrinkly]

However it was not by picking numbers out of a hat that we ended up with the M2, M4, M6, M11, M18, M20, M23, M25 (which originally included what is now the M26), M27, M40, M45, M48, M56, M58 and M62 all to a greater or lesser extent shadowing the corresponding-numbered A roads.

[thomas417]

While it would be nice for the whole thing to be M6 I understand how politically this would be difficult to achieve. What really needs to be sorted is renaming the A74(M) and I'd be happy with that as it makes some sense at least. M6 in England, M74 in Scotland.

It's ridiculous that a key national motorway, the longest in the UK which links two nations, has such an aborted numbering scheme.

[Cryoraptor]

It doesn't stay as the M6 because the Scottish government doesn't want it to. At one point in time the A74(M) and most likely the M74 were planned to eventually join the M6, but this like many British road network projects fell apart and we were left with what we have now minus a few things like the Cumberland Gap at the time.

Eventually we will probably see A74(M) signs slowly replaced with M74 ones as they are effectively now the same road and have been for over a decade, but as long as the SNP are in charge and keep independence on the agenda, they will never agree to a continuous M6. I wouldn't be surprised if they started trying to get the A1 and other such cross-border roads renumbered past the border at some point. I don't think anyone wants to talk about what would happen with the Scottish road network if independence were to happen, namely shared roads like the A1. I suppose the one positive is that we would be able to add the final 300m or so of A74(M) on the English side to the M6, which is some sort of consolation for the complete mess of the corridor.

has such an aborted numbering scheme

Welcome to the UK, where we call the M38 the M5 for some reason or another.

[Euan]

I think the motorway numbering for the Cumberland Gap may have been a bit more uncertain if the A74(M) had all been designated as the M74 once it was built. If you ended up with the numbering sequence M74 -> A74 -> M6 it might have made a bit more sense visually for the old A74 to become the M74 north of Carlisle. The way it has turned out the only alternative to using M6 would have been to use A74(M) and I think there would be a desire to minimise use of that bracket notation where possible/feasible given its hardness on the eye.