ibid: The first time a source is mentioned, you must give the citation in full. If a subsequent citation IMMEDIATELY follows the full citation, you can use ibid.
Using n# means the writer doesn’t have to repeat all the bibliographic information, but instead refers the reader to n# (footnote #) for all the bibliographic information.
Full citation for a case:
1 Phelps v Hillington LBC [2001] 2 AC 619 (HL).
Subsequent citation immediately after the full citation:
2 ibid.
Subsequent citation using shortened form of case name and a cross-citation to footnote 1 where the full citation can be found
10 Phelps (n 1).
Full citation for a book:
1 Robert Stevens, Torts and Rights (OUP 2007).
Subsequent citation using shortened form and a cross-citation to footnote 1 where the full citation can be found and subsequent citation immediately after cross-citation to footnote with different pinpoints.
6 Stevens (n 1) 110.
7 ibid 271–78.
The writer 'pinpoints' page 110 and 271-78 showing the reader the information for those footnotes was taken from those specific pages.
Subsequent citation for legislation:
Full citation with name of statute and shortened version in brackets:
32 Nuclear Installations Act 1965 (NIA 1965) s 7(1).
Subsequent citation using shortened version of the statute
40 NIA 1965, s 12.