I know this makes me sound like one of the WP admins, but I think we really need some sort of notability limitation.

When adding counties to roads, I have found many pages (such as B5120) which have been added because of mis-quoted numbers in newspapers, among other sources.

Also, is the A36(M) only given a page because of a SABRE conversation? If that's the case, should we give a page to, say, M14, as some on SABRE have suggested that M14 was supposed to be Ringway 1's number (typo'd to M41).

Since you're not American and you have expressed an interest in British and Irish Roads, I don't think you'll ever sound like one.

We generally have an unofficial rule that if somebody spots something that can be challenged, they can ask about it. The reason that works here and not on Wikipedia, is that the latter is far bigger in scale and any non-expert can challenge an expert.

We also assume, and with very good reason, what is reported on CBRD, PM etc is correct, and can be frequently validated via the archive folders referenced on CBRD ArchiveWiki.

Also, what's the issue with the B5120 article? If I click on the map reference next to the start or endpoints, I get contemporary OS coverage that matches up. It's been rerouted westwards sometime after 1960, but otherwise has been in Prestatyn since 1923.

Well, I'd be happy to bin the A36(M), but it's gone beyond "a SABRE conversation". As for the "M14", it was a tongue-in-cheek suggestion only, with no basis in reality or outside sources.

Chris put it best:

The question is, though, when should it stop?

I have a 1960s diary that has an enclosed map (which some you have seen). In the map, the M45 is shown as numbered M5. Should I create a whole M5 (M1 spur) page based on that mapping error?

I'm no expert on the Sabre wiki (although I am a WP admin ), but I'd say that there should be content about such mapping errors, with search terms for them redirecting to that content. That's not to say there should be a page about every mapping error, but for example in this case a sentence on the M45, M5 and/or a central mapping error page, noting that this diary mislabelled the M45 as the M5.

I don't think mapping errors on things like leaflets are even worth mentioning- they're so wrong so often.

If it's a map, designed purely to be a map then fair play, I'd make an article for it.

I think common sense is a major factor, seemingly unlike the 'other' wiki.

If people are likely to be asking about it, then there should be a page about it. A degree of judgement and common sense is required.

Exactly. If it's a massively obvious error, such as on OS maps, Google Maps or some other commercial map maker, (or indeed an official or semi-official source) then that's in there. If the South Suffolk Messenger misprints the Ipswich Bypass in an advertisement, then so what? If it's in the middle, then you make a judgment call.

That's what I was getting at, better put

That's one of the reasons why I added famous fantasy schemes, like the East Coast Motorway and POLO. Ditto the fairly solid hearsay about the plan for M27 spur numbering meaning that there's M270, M273 (that's just a redirect to the Townhill Link Motorway page, IIRC) and M274 pages. These things come up quite a bit on SABRE, and elsewhere, so we want pages on these.

A36(M) is on the wiki as it was in the digest, IIRC. It can surely stay as a page linking to PM.

Things like the A11(M) and A23(M) provisional numbers, and the M30 M3 renumbering plan get included as on official documents - just like the ones already on PM.
Hence I've added the A65(M) now I got my scanner working (the scan I did yesterday didn't work well, and I couldn't be bothered to re-do it - it's wasn't done to annoy you Lenzar, or because I didn't think it was notable enough before Steven's post) and could provide a scan of the offending map.