[3][4][5] Clay received a commercial education and his son's memoir states that he attended just one school, with Mr Wylie.

[1] At age 21 and out of work, Clay came on a visit to Cooper Hill, Charles Swainson's home in Walton-le-Dale near Preston, around 1817.

Swainson persuaded Clay to study for the priesthood, and he was tutored by Robert Harris of Preston Grammar School, in the Greek Testament.

[8] With the chaplaincy as "title for ordination", he was ordained deacon at Kendal on 11 August 1821, a "literate", by George Henry Law.

[1][8][9] On 22 September 1822 Clay was ordained a priest, and soon after was entered as a prospective "ten-years man" at Emmanuel College, Cambridge.

[1] Preston gaol, under James Liddell, had already innovated by setting prisoners to work in textile companies; that started shortly after his appointment in 1817, and attracted attention.

Joseph John Gurney giving evidence to a parliamentary select committee on gaols in 1819 was positive about the initiative, but pointed to a lack of religious instruction.

[14] Under Clay's influence, the Lancashire magistrates permitted the introduction of the separate system at Preston and Kirkdale Gaol, Liverpool, from 1847.

George Heaton of Gloucester County Jail, and Whitworth Russell of Millbank Penitentiary, rather than the more moderate Thomas Fowell Buxton and Elizabeth Fry.

His opinion of the general behaviour of the strikers was high, as expressed to Henry Ashworth; on the other hand he considered that the months of idleness had had a bad effect on the morals of the young women.

[21] Lord Harrowby, as Chancellor of the Duchy of Lancaster, offered Clay, when he was in financial difficulty, the rectory of Castleford.

The details of prison management in time yielded an octavo volume and made him an authority on criminal reform.

[26] His thesis, read in the terms of correlation of the business cycle and sectors of criminality, is concerned with countercyclical variables.