John (ca 1688–1770) and William Bastard (ca 1689–1766) were British surveyor-architects, and civic dignitaries of the town of Blandford Forum in Dorset. John and William generally worked together and are known as the "Bastard brothers". They were builders, furniture makers, ecclesiastical carvers and experts at plasterwork, but are most notable for their rebuilding work at Blandford Forum following a large fire of 1731, and for work in the neighbourhood that Colvin describes as "mostly designed in a vernacular baroque style of considerable merit though of no great sophistication.". Their work was chiefly inspired by the buildings of Wren, Archer and Gibbs. Thus the Bastards' architecture was retrospective and did not follow the ideals of the more austere Palladianism which by the 1730s was highly popular in England.
The brothers, the sons of Thomas Bastard (died 1720), a joiner and architect, the founder of a family firm of provincial architects in the area. However little remains today of the works of the brothers' ancestors, chiefly as the result of the 1731 fire and a previous fire in the town in 1713.
On 4 June 1731 a fire destroyed the greater part of Blandford. John Bastard worked as a fire assessor before and after this fire, and a book survives in Dorset History Centre in which he detailed assessments from fires at Sturminster Newton Castle (1730), Affpuddle (1741), Beaminster (1741), Puddletown (1753) and Wareham (1762). The inventory for the fire at Blandford shows the losses of everyone in the town including the Corporation of the Borough of Blandford and the church. Bastard and Co. were the largest private losers.
The Blandford fire, which swept away the heart of a town that had evolved in a haphazard way from the medieval period, presented an opportunity for more regular redevelopment in the classical styles. However, with the exception of a widening the original market square, the fashionable Baroque style of town planning was ignored and the town was rebuilt on its former medieval street plan.