Ancestry.co.uk have just announced the release of new online digital images from The National Archives: Home Office Criminal Registers for England and Wales under Series HO 26 and HO 27.
These registers cover the period 1791-1892. The database is fully searchable by name and other information supplied may include age, birthplace (not after 1802), crime, sentence and when and where tried.
I have just tried a few random searches and most of the registers cover Middlesex, but other places are listed including 33,646 individual entries involving trials at the Assizes in Essex.
On their own, the problem with the registers is that only the name is supplied. No date of birth or address, nor where the offence took place. Nothing to add confirmation that it is the person you are looking for. However, as the date of the trial or law session is given, you can the use this information to try other sources such as Indictment Records and newspapers at the Essex Record Office. (See our Essex Court Cases page).
Other records to consult are Calendar of Prisoners, Prison Registers, Warrants, including pardons, reprieves, and transfers of prisoners and Transportation records.