B roads are numbered routes in Great Britain of lesser importance than A roads. See the article

Great Britain road numbering scheme In Great Britain, there is a numbering scheme used to Categorization, classify and identify all roads. Each road is given a single letter (representing a category) and a subsequent number (between one and four digits). Though this scheme was in ...

for the rationale behind the numbers allocated.

Zone 1 (3 digits)

Zone 1 (4 digits)

{{DEFAULTSORT:B Roads in Zone 1 of the Great Britain Numbering Scheme 1 1