Cases from the UK are published in many reporters, both official and unofficial, and online in several databases.  The new Bluebook (19th ed.) gives the names of the reporters considered authoritative and a list of acceptable online services.  In fact, for cases after 2001, a neutral citation from BAILII, the British and Irish Legal Information Institute, is required (T2.42, p.408).  An example of a neutral citation is, Glasgow Corp. v. Central Land Board, [1955] UKHL 7.  

Cases from England and Wales are often sought after for sourcecites and general research.  As explained in the Bluebook (T2.42.1, p.414), cases after 1865 are published in and should be cited to the official Law Reports, which consists of many different sets of reporters including

• Appeal Cases (A.C.) - KD275.4
  • Related earlier reporters in this series are: 
    
    • English and Irish Appeal Cases - KD275 .L39
      
    • Scotch and Divorce Appeals - KD275.2 .L39
      
    • Privy Council Appellate - KD275.3 .L39
      
• Chancery Division (Ch.) - KD276.3 .L39
  
• Queen's Bench (Q.B.) - KD277.7 .L39
  
• King's Bench (K.B.) - KD277.7 .L39 (same as above, but when a King reigned)
• Probate Division (P.) - KD279.3 .L39
• Family Division (Fam.) - KD279.4 .L39 (replacing Probate Division in 1972)

If the case cannot be found in Law Reports, you can use the following reporters, in order of preference:

• Weekly Law Reports (W.L.R.) - KD282
  
• All England Law Reports (All E.R.) - KD288 .A64

There are still more print reporters that can be used if needed, such as:

• Lloyd's Law Reports (L.L.R.) - KD1815 .A2 .L57
• Human Rights Law Reports - UK Cases (H.R.L.R.) - KD4080 .A38 H86
• UK Human Rights Reports (U.K.H.R.R.) - we do not have
• International Law Reports (I.L.R.) - KZ199 .I58
  

Finally, you can find cases from the United Kingdom in several databases:

• BAILII (free)
• Lawtel (subscription)
• Justis (subscription) - also includes access to International Law Reports (I.L.R.)
  
• Westlaw and Lexis (Passwords)

As always, please feel free to see a librarian for assistance in this complicated quest.  Also see this research guide.

London's Old Bailey Criminal Court cases 1674-1913 are now searchable online.  The Proceedings of the Old Bailey,1674-1913 include transcripts of 197,745 criminal trials held at London's Central Criminal Court between the years 1674-1913.  Other than chronicling a string of sensational trials in London in the period, the free website was also billed as "the largest single source of searchable historical information about British lives that has ever been published". See full story here.