During the 1930s, the BMMO network was expanding rapidly and the company was starting to run out of numbers that were available to use on new routes. To solve the problem, local bus networks were renumbered with numbers prefixed with a letter to denote the area. Thus, on Monday 7th January 1935, all local services in Malvern were renumbered with @#8216;M’ route numbers, and Service 373 became Service M23.
The route for “Round the Hills” Service M23 was the same as that for the predecessor, Service 373, and like that service, it was only operated during the summer period with three journeys each day in each direction, Monday to Saturday, and two journeys in each direction on Sundays. Service M23 was operated by Worcester depot, probably using vehicles housed at their Portland Road “dormy garage” in Great Malvern on some or all journeys.
For the 1936 season, the Saturday operation of Service M23 was withdrawn, but the service continued otherwise unchanged on other days of the week.
Following the declaration of war on Sunday 3rd September 1939, many bus services throughout the country were suspended, but BMMO closed their summer season and suspended Service M23 as scheduled on Saturday 23rd September 1939. Surprising, Service M23 was reinstated for the 1940 summer season and continued to operate throughout 1940, until the end of the season in September 1940 as normal. At this time, Service M23 was withdrawn and like many of the pre-war summer services was not reintroduced by BMMO after the war came to an end, and despite calls for its return from members of the public, “Round the Hills” Service M23 never returned.
| M | 2 | 3 |
| July | 1938 | Great Malvern ↔ West Malvern ↔ British Camp |