If the name of the case naturally fits in to flow of paragraph, then you need only insert the rest of the citation in the footnote at the base of the page:
The Court of Appeal's judgment approves, with slight amendments, the guidelines set out by the Employment Appeal Tribunal in Barton v Investec Henderson Crosthwaite Securities Ltd. 2
…
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2 [2003] ICR 1205.
If the main body of the essay refers to a case or cases, but doesn’t explicitly name them, then the whole citation must be placed in the footnote at the base of the page:
Recent cases on controlling or coercive behaviour 1 ...
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1 R v Maguire [2019] 2 Cr App R (S) 55; R v Dewhurst (Anthony Paul) [2021] EWCA Crim 663.
To find out how to reference cases see the guide on OSCOLA which can be found at https://www.law.ox.ac.uk/published/OSCOLA_4th_edn_Hart_2012.pdf
