It is rare that a complete set of records for a court case -- briefs, documents produced by the parties, and a transcript of the trial -- survive for the use of historians. Only the final judgment is likely to be recorded, and it will be published only if the case is significant. Finding trial transcripts, as a result, is a matter of luck. For example, currently, most British courts keep recordings of trials for about 6 years; the researcher must pay for a transcript to be made of the recording.
The National Archives of the United Kingdom has published a number of guides to the records, e.g. "Tracing 18th, 19th and 20th Century Criminals" and "Old Bailey and the Central Criminal Court: Criminal Trials." There is an index the the guides at http://www.nationalarchives.gov.uk/catalogue/researchguidesindex.asp.
Notable British Trials series
We hold only a few volumes of this long-running series, which begins in 1905. Search Worldcat for the others. A few, published before 1926, are in Making of Modern Law: Trials, above.
Cobbett’s complete collection of state trials and proceedings for high treason, and other crimes and misdemeanor from the earliest period to the present time ... from the ninth year of the reign of King Henry, the Second, A.D.1163, to ... [George IV, A.
Published/Created: London, R. Bagshaw [etc.] 1809-26.
Firestone Library (F) KD371.P6 H694 (33 v.; does not circulate) -- also in Rare Books Off-Site Storage and online in Making of Modern Law: Trials