The London-Liverpool mail coach started about 1785.  This advert is from 1813, by which time the Royal Mail's network of mail coaches had expanded with coaches between Liverpool and Birmingham, Bristol, Chester, Holyhead, Shrewesbury & Manchester.

Passengers could be carried on these coaches. Note that some are advertised as being  "well lighted and guarded"  because certain routes were prone to attack by highwaymen, mobs and other vagabonds!