prisoners would also be used as menial labour, walking on wheels to spin looms or run a water wheel. This would decrease the cost of the prison and give a possible source of income. The ultimately abortive proposal for a panopticon prison to be built in England was one among his many proposals for legal and social reform. But Bentham spent some sixteen years of his life developing and refining his ideas for the building and hoped that the government would adopt the plan for a National Penitentiary appointing him as contractor-governor. Although the prison was never built, the concept had an important influence on later generations of thinkers. Twentieth-century French philosopher Michel Foucault argued that the panopticon was paradigmatic of several 19th-century "disciplinary" institutions. Bentham remained bitter throughout his later life about the rejection of the panopticon scheme, convinced that it had been thwarted by the King and an aristocratic elite. Philip Schofield argues that it was largely because of his sense of injustice and frustration that he developed his ideas of "sinister interest"—that is, of the vested interests of the powerful conspiring against a wider public interest—which underpinned many of his broader arguments for reform. On his return to England from Russia, Bentham had commissioned drawings from an architect, Willey Reveley. In 1791, he published the material he had written as a book, although he continued to refine his proposals for many years to come. He had by now decided that he wanted to see the prison built: when finished, it would be managed by himself as contractor-governor, with the assistance of Samuel. After unsuccessful attempts to interest the authorities in Ireland and revolutionary France, he started trying to persuade the prime minister, William Pitt, to revive an earlier abandoned scheme for a National Penitentiary in England, this time to be built as a panopticon. He was eventually successful in winning over Pitt and his advisors, and in 1794 was paid £2,000 for preliminary work on the project. The intended site was one that had been authorised (under an act of 1779) for the earlier Penitentiary, at Battersea Rise; but the new proposals ran into technical legal problems and objections from the local landowner, Earl Spencer. Other sites were considered, including one at Hanging Wood, near Woolwich, but all proved unsatisfactory. Eventually Bentham turned to a site at Tothill Fields, near Westminster. Although this was common land, with