Buses in Portsmouth are a form of public transport in the city of Portsmouth, England. Motor bus services in Portsmouth began in 1919, and were expanded in the 1930s following the closure of the Portsmouth Corporation Transport tram network. Trolleybuses were also operated between 1934 and 1963. Until 1988 the majority of services were provided by Portsmouth Corporation Transport, a municipal bus company owned by Portsmouth City Council. Other services into the city were operated by Southdown Motor Services, latterly as a subsidiary of the National Bus Company.