It's welcome to have online availability of this talk from 10 February 2011 by Jeff James who is Director of Operations and Services at The National Archives. In this day and age it's refreshing to have a manager showing a disciplinary knowledge of the organization's work.
Using three individuals, the podcast takes researchers through the various stages of the criminal justice system of the period and focuses on the various records created, from the commission of a crime, through the court processes and on to the records of punishment.
He makes the point that as criminal cases were crimes against the Crown, pardons were at (delegated) royal discretion. They were common in the period in question. Thousands of felons convicted of a capital crime, of which there were many, had their sentences reduced.
The England & Wales, Criminal Registers, 1791-1892, available with a free index at Ancestry and taken from TNA Series HO 26 and HO 27 are mentioned as a good starting point covering cases handled at the Assizes courts.
I enjoyed this talk more than many in the podcast series. It's available at http://www.nationalarchives.gov.uk/podcasts/criminal-records.htm