The company was founded in Lowestoft, Suffolk in May 1912, with two routes. One route operated in Suffolk, with the other operating over 200 miles away in County Durham, between Bishop Auckland and Durham.
United also started East Midland Motor Services. This came about through the desire to expand. One of their managers, W.T. Underwood, was sent to Clowne (near Chesterfield) to set up a bus company in his own name. The Underwoods company later became East Midland.
The company ran vehicles from its head office in Darlington and garages across their area, including Durham, Hartlepool, Whitby and Peterlee amongst others. Most of those vehicles were Bristols with Gardner engines and Eastern Coach Works bodies, the LH and VR being common vehicles. Another vehicle commonly used was the Leyland National. United were one of only three operators (and the only English operator) to buy the Bristol REMH 12-metre (39 ft) coach chassis.[4] These 35 vehicles, which had Plaxton Panorama Elite III 49-seat coach bodywork, were delivered between 1971 and 1975.[4][5]
In the mid-1980s, following the deregulation of bus services, a number of Dodge and Mercedes-Benz minibuses were purchased by United for use on local services. Some routes replaced existing "big bus" services, with others operating on brand new services, which were highly competitive with existing services operated by the local authority – notably in Darlington and Hartlepool.
Most of these minibuses were branded with names such as Darlington Roadranger, Hartlepool Hoppa, Peterlee Panther, Whitby Clipper amongst others. These new minibus routes ran around housing estates to a Hail and Ride system and after some initial controversy, these services proved successful for United, most notably in Darlington where the minibus network was hugely expanded.
On 2 December 1987, as part of the privatisation of the National Bus Company, United was sold to Caldaire Holdings who had earlier purchased West Riding Automobile Company.[9][10][11]