The first building on the site on the east side of the High Street between Silver Street and Soapers Lane was a public house known as the "Wine Tavern" which dated back at least to 1590.[2] It was acquired by an apothecary, John Gayner, who converted it for his own use in 1737.[2] The site was then acquired by an attorney, George Rolph, who decided to demolish the original building and commission the current structure.[2]
The new building was designed in the neoclassical style, built in brick with a stucco finish and was completed in 1785.[3] The design involved a symmetrical main frontage with three bays facing onto the High Street; the central bay featured a portico with Ionic order columns supporting an entablature. The outer bays were fenestrated by tri-partite sash windows and, at roof level, there was a modillioned cornice and a parapet. Internally, the principal room was a large drawing room at the front of the building on the first floor.[3] Following George Rolph's death in 1815, the house passed to his son, William,[4] who enlarged the property by incorporating two other properties at the rear.[3]
Following William Rolph's death in 1848, the building was auctioned and acquired by the local justices of the peace.[3] They commissioned a local contractor, Daniel Burchell, to convert the building into a police station and courthouse.[3] Accommodation for the police sergeant and constables was created at the rear of the building. The drawing room was converted into a courtroom, which opened in time for the quarter sessions in March 1860.[3][5] A large circular plaster cast recording the new use of the building and the date of the conversion was installed on the front of the building at first floor level.[6] The borough council, which had ceased to discharge the usual functions of a corporation,[7] was abolished under the Municipal Corporations Act 1883.[8]
Thornbury Rural District Council, which was established in 1894,[9] was not involved in the operation of the courthouse and instead established itself in council offices in Castle Street.[10] The building in the High Street continued to operate as a police station until 1973, when a new police station opened in Rock Street, and continued to host magistrates court hearings until 1986, when the magistrates moved to a modern courthouse in Yate.[3][11] The building then remained empty and deteriorating until it was acquired by Thornbury Town Council in April 1992. Restoration works, which involved the conversion of the courtroom into a council chamber, were completed in 1994.[3] The old custody cells in the police station were restored for use as a visitor attraction[12] and a tourist information centre was established on the ground floor of the building.[13]