On the second of April 1921 Stockton Corporation and Thornaby Corporation jointly formed a committee to operate the forme tram services of Imperial Tramways in the towns and services restarted on the 4th April. The assets were split between the two Boroughs. Stockton Corporation owned the two depots, Norton and Bridge Road, with its adjoining power station but the track bed was owned by each of the authorities in which it lay. Nine double-deck cars were acquired by Thornaby Corporation and twenty by Stockton Corporation. A small number of motorbuses from the Imperial fleet were owned by Stockton..

By 1929 Stockton Corporation had decided that it wished to replace its tramcars with motorbuses and despite opposition by Thornaby and Middlesbrough Corporations finally did so at the end of 1931 when the Norton Green to Middlesbrough services were replaced by motorbuses. A further service jointly with Middlesbrough was initiated running via Thornaby and Acklam to Middlesbrough Town Hall from 1932.

Thornaby Corporation sold its tramway interests to Stockton on 1st August 1930, and in November 1931 Stockton combined its tramway and omnibus committees into a single Transport Committee in anticipation of the tramway abandonment.

Various motorbuses had been purchased by Stockton throughout the 1920s from a variety of manufacturers including A.E.C., Ford and Dennis and, from 1928, the new Leyland TD1. In 1930 and 1931, a series of trials was conducted with vehicles designed to replace the tramcars. Daimler, Thornycroft, Sunbeam and Maudslay buses were tried but only a single Crossley Condor and A.E.C. were bought, Daimler vehicles being adjudged most suitable.

Local operators Layfield and Harewood were purchased to consolidate services in 1932.

Further batches of petrol engine Daimler double deck vehicles followed and a batch of Leyland Titans in 1938. The war years saw many changes to services and vehicle policy. Stockton was allocated vehicles by the Ministry of Supply but had to negotiate loans of vehicles from the London Passenger Transport Boad, Manchester Corporation and Yorkshire Woollen District Transport Company, among others, to enable it to meet the additional traffic that was generated by the war effort on Teesside.

After the cessation of hostilities, more Daimlers were obtained as well as a batch of Bristols to replace worn out 1930s stock. From 1949 onwards Leyland Titans were the Corporation's choice, but with an assortment of manufacturers building the bodywork.

The fleet had only received double deck buses since 1931 but two second hand Leyland Lions were obtained in 1948 and a new Leyland Olympic in 1951 for use on the service to Yarm via Hilton. This was an unusual vehicle as it had front and rear entrances when delivered; it was subsequently converted to single front entrance in preparation for one-man operation. A further second hand A.E.C. Regal was obtained from City of Oxford Motor Services and finally a batch of high capacity Leyland Panther Cubs was bought new in the middle sixties, followed by ten Leyland Panthers in 1967.
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After further trials in 1962, new Leyland Atlantean double-deckers were bought for the rapidly expanding services in Thornaby, Roseworth and Billingham.

Towards the end of 1966 the impending amalgamation of the Teesside fleets into Teesside Municipal Transport, saw greater co-operation with Middlesbrough Corporation on joint routes. By the end of that year, turquoise vehicles were being delivered, still proudly bearing Stockton Corporation Fleet names.

Fred Gilbert

The vermilion and white livery of Imperial Tramways was kept for the tramcars but the fleet name "Stockton and Thornaby Corporations", together with the crests of the two Boroughs was added to the lower panels. Buses also bore this livery but had a white roof.