After the acquisition of Hampshire Bus by the Stagecoach Group in early 1987, it was thought that it would only be a matter of time before Routemasters were to be seen on the streets of Southampton. During May 1987 the Stagecoach Group once more started a series of Routemaster purchases which were all placed into store at the former Hampshire Bus Overhaul Works at Barton Park, Eastleigh. 

However, it was with Southampton CityBus that RM operation was to commence when on Friday 29 May 1987 crew operation was restored to the streets of the city on new service 16 between the city centre and the Millbrook Estate. The acquisition and subsequent entry into service by CityBus's Routemasters was a particularly rapid operation and was primarily in direct response to the antics of the newly formed Southern Vectis subsidiary, Solent Blue Line, who had launched a predatory strike on some of CityBus's traditional and most lucrative services a few days earlier. The Blue Line fleet was a collection of older Bristol VRs of varying ages, but were operated with a conductor. 

Southampton CityBus acquired 12 Leyland engined Routemasters although only six buses were required for the 16. All were painted in standard Southampton red with off white relief. Large CityBus fleetnames were fitted and black and yellow vinyls were applied extolling the virtues of the service and encouraging passengers to 'hop on at the back'. The balance of Southampton's Routemasters entered service from Friday 3 August when crew operation was introduced to routes 17A and 23. Route 17A operated from Millbrook to Weston via the City Centre, whilst the 23 operated between Thornhill and the City Centre. This second batch of RMs featured the same livery but with smaller City-Bus fleetnames.  From this date all 12 of Southampton's Routemasters were in service for four months before another route restructuring took place. In October 1987 Stagecoach sold the entire Southampton-based operation of Hampshire Bus to Southern Vectis who amalgamated it with their Solent Blue Line operation. Approximately 80 vehicles came with the business but the Routemasters at Barton Park were kept and subsequently moved on to the Glasgow-based fleet. 

In early 1988 another five buses were taken into stock and these were finished in the same all over red livery style initiated by 414 (RM820). These five RMs were allocated fleet numbers 415-41 9 and all entered service during April 1988, replacing five earlier acquisitions. Over the following few months the Routemasters were all withdrawn. and this episode drew to a close.

An unidentified RM on the original route 16 seen here in central Southampton.

RM 1383 Southampton 405 (363 CLT) at the city centre terminus to the rear of Marks & Spencer. It is about to depart to the Millbrook Estate

From the second batch of RMs, RM 2043 (Southampton 412 ALM 43B). These had a much more restrained style of fleetname than the original batch. It is seen here at Thornhill 

RM 1383 Southampton 405 (363 CLT) again. This time it is in Shirley.

RM 2037 (404 - ALM 37B) in Above Bar Southampton. Note that the route 16 branding has been replaced with something more generic. Also note the Atlantean behind in the reversed red and cream livery carried in SCTs later days.