When available, use an official neutral citation before the report specific citation.
The House of Lords, Privy Council and Court of Appeal adopted neutral citation in 2001. All Supreme Court judgments have a neutral citation. The courts and divisions of the High Court adopted neutral citation in 2002 (except for the Administrative Court, which adopted neutral citation in 2001).
Eg Nationwide Building Society v Dunlop Haywards (DHL) Ltd [2009] EWHC 254 (Comm), [2010] 1 WLR 258.
Appendix 4 sets out the full list of court identifiers used in neutral citations.
Note that some earlier decisions have been given what look like neutral citations by the British and Irish Legal Information Institute (BAILII). These are not official and should not be used.