Kempthorne was a pupil of Annesley Voysey (c.1794-1839) and partner of Richard Suter, the Surveyor of the Fishmonger’s Company.

Sir George Gilbert Scott formed a friendship with Kempthorne, who was two years older, and found him to be ‘a very worthy & religious young architect & I used occasionally to follow at Mathematics with him’. In 1833, Kempthorne was admitted as a student to The Royal Academy.

In December 1834, Sir George Gilbert Scott visited his brother, Thomas, at Goring and it was there that he received a letter from Sampson Kempthorne ‘telling me that a set of chambers next his in Carlton Chambers Regent Street, was vacant, & that if I liked to take them, he could find employment for my leisure time, in assisting him with his Union Workhouses’. Kempthorne’s influx of work came from the enactment of the Poor Law Amendment Act of 1834, which aimed to ensure a better standard of provision for the poor. Three Commissioners were appointed on 18 August 1834 to ensure that the provisions of the Act were carried out and one of these, George Nicholls (1781-1865) was a friend of Kempthorne’s father. Consequently Kempthorne was given the job of preparing standard designs for the new union workhouses.

Ten of Kempthorne’s standard designs for different sized workhouses were published as an appendix to the first report of the Poor Law Commissioners in 1835. This shows a variety of plain classical structures as an entrance block with various forms of segregated accommodation wings for men, women and children in three stories projecting from the rear. The Architectural Magazine declared that Kempthorne’s barrack-like model plans were ‘excellently arranged’.

When Sir George Gilbert Scott set up on his own by moving into Carlton Chambers, next to Kempthorne, he was clearly thinking that his practice would be similar to those he had already experienced, which were typical of the 1830’s, and his enthusiasm for medieval buildings was only a pleasurable pastime with little relevance to architecture. Kempthorne’s call for assistance on his workhouses must have seemed to Scott to have been the ideal arrangement. He would have a modest income to pay his rent and living expenses, which it seems were very simple, and the opportunity to build up his own practice. But by the 1860’s, Scott would have wanted to disassociate himself from Kempthorne, calling his work there ‘more mean even than that of my pupilage’. But perhaps the break was more gradual than is suggested.

Sir George Gilbert Scott had only a few weeks of workhouse experience at the time he quit Kempthorne’s in 1835 and could not have been considered an expert unless he claimed an association with Kempthorne, who was the acknowledged authority on workhouse design. The two men continued to occupy adjacent offices at Carlton Chambers until 1837, when Kempthorne moved to Clarages Street off Piccadilly. It therefore seems probable that they remained on friendly terms and had informal professional contact. Scott’s somewhat unsatisfactory account possibly stems from embarrassment at the way in which he used his friend’s name to further his ambitions and start his own practice.