Findmypast.co.uk have released a substantial number of new records under the overall title of
Crime, Prisons & Punishment 1770-1934
The current 518,000 records help you discover if your ancestors were criminals and passed through the justice system in England and Wales between 1817-1931. Soon it will be extended to cover the years 1770 – 1934 with thousands more additional records.
Many contain information on criminals from Essex.
They are from a number of sets of records at The National Archives:
Admiralty: registers of convicts in prison hulks (TNA ref: ADM6)
Central Criminal Court: after-trial calendars of prisoners (TNA ref: CRIM9)
Home Office: calendar of prisoners (TNA ref: HO140)
Home Office: criminal petitions (TNA ref: HO17)
Metropolitan Police: Criminal Record Office: habitual criminals’ registers and miscellaneous papers (TNA ref: MEPO6)
Home Office and Prison Commission: prison records (TNA ref: PCOM2)
More details on this page on their website: Crime, Prisons & Punishment 1770-1934