Portsmouth Corporation was sold to Southampton CityBus in 1988 who rebranded the operations as Portsmouth CityBus. Its existing operations in the area, Red Admiral became a subsidiary of the new company.
In 1989, Stagecoach purchased Portsmouth CityBus.
In 1989, Stagecoach purchased Portsmouth CityBus. It merged the company with the majority of its existing Southdown routes in Portsmouth resulting in Southdown Portsmouth. Stagecoach were forced to sell the company to Transit Holdings in 1991.
Transit Holdings operated services under the Portsmouth Transit, Blue Admiral and Red Admiral names, the latter was previously used by Portsmouth CityBus between 1988 and 1989.
Portsmouth Transit was sold to FirstBus in 1996, which shortly after combined it with its existing operations in the area, First Provincial.