At first glance, Zone 5 appears to be one of the biggest, it certainly seems to cover a lot of the country, but with the A5 and A6 still running pretty close together near Leicester, there are few roads needing Zone 5 numbers in the London area. The bulk of the numbers, therefore, cover the North West Midlands, Cheshire, Lancashire, the Lake District and a thin sliver of North Wales.
While Zone 5 may not be the biggest, it is surprising that neither the A598 or A599 numbers were allocated in the initial 1922 Road Lists. When compared with Zone 4 to the south, where it appears that many A4xxx numbers were allocated, it would have perhaps made sense to move the A5 southwards, and pass it through Birmingham on Telford's Road to equalise the areas a little better.
- A5 London - Holyhead
- A50 Leicester - Warrington
- A51 Tamworth - Birkenhead
- A52 Nantwich - Grantham
- A53 Shrewsbury - Buxton
- A54 Chester - Buxton
- A55 Chester - Bangor
- A56 Chester - Broughton (Skipton)
- A57 Liverpool - Lincoln
- A58 Liverpool - Wetherby
- A59 Liverpool - York
The 3-digit roads covered the zone as follows in 1922:
- A500-A504 Greater London
- A505-A510 Bedfordshire, Northamptonshire & North Buckinghamshire
- A511-A522 Leicestershire, West Derbyshire & North Staffordshire
- A523-A540 Cheshire (some very long routes extending into N Wales)
- A541-A550 North Wales
- A551-A572 Northern Cheshire / Southern Lancashire (Merseyside)
- A573-A580 South Lancashire (Greater Manchester)
- A581-A589 Preston & North Lancashire
- A590-A597 Lake District
- A598-A599 Not Used.
There were, of course, many B-roads marked out in those very early years, with most of the numbers from 500-599 and 5000-5446 having been used at some stage. As with the other zones, the numbers started in London and then increased the further from the Capital they were. The original allocation seems to have run out somewhere near B5307 at Carlisle, but judging by the importance of some of the higher numbers, lots of additional routes must have been allocated right from the beginning.