Maybe its because they are Londoners

The archetypal London Bus, RML2391 arrives at Pleasure Beach on route 12. 

A London Trio. Blackpool Transport City Sightseeing branded Olympian 873 once London Buses L173 is followed by RM1568 at Tower with RML887 heading north in the distance

Seeing Double (or triple). The ten minute interval on route 14 has clearly gone awry as three Tridents head to Mereside together at Bank Hey Street. The two nearest the camera are 340 and 341, new to independent Blue Triangle (now part of Go Ahead) for use on Transport for London Tenders