It was one of the largest English bus companies, operating over a large area between Gloucester in the south and Derbyshire in the north, and from Northampton to the Welsh border.

[1] When the directors failed to attract sufficient investors, BET acquired control of the new company, and in 1905 transferred its local horse bus operations to it.

During the 1920s the tramways owned by BET in the Black Country were gradually replaced by Midland Red buses.

A fleet of ten, capable of speeds of up to 85 miles per hour (140 km/h), were built at the company's workshops at Edgbaston.

Between 1923 and 1969, the BMMO built most of the buses it operated: up to 1940 these were called SOS (rumoured to stand for Superior Omnibus Specification), and some models were supplied to other bus companies associated within the British Electric Traction (BET) group, namely Trent, PMT and Northern General.

The D10 was, in some opinions, the pinnacle of BMMO bus design – a double decker with front entrance/rear exit and an underfloor engine, but only two were produced.

AD2, GD6 and LD8 were exceptions to the normal designation system – these codes referred to batches of respectively AEC, Guy and Leyland vehicles acquired when the manufacturing operation could not meet the heavy demand.

Bus manufacture, overhaul and accident repair was carried out at Carlyle Works, adjacent to the Rotton Park Reservoir in Edgbaston, Birmingham.

Other short time-span garages (either owned or rented) included: Birmingham, Ladywood Road (Five Ways Inn yard); Coventry, Sandy Lane; Cradley, (GWR station yard); Halesowen, Mucklow Hill (GWR station yard); Hereford, Bridge Street (Black Lion Yard); Kingswinford, The Portway; Leicester, Frog Island; Leicester, Hastings Road; Leicester, Welford Road; Nuneaton, Burgage Walk (ex NWMO&T Co); Nuneaton, Heath End Road; Nuneaton, the former Empire theatre; Sedgley, WDET Co depot; Shrewsbury, Abbey foregate (ex Allen Omnibus Co); Shrewsbury, Roushill; Stafford, Co-operative Street; Wellington, Mansell Street.