The major UK research councils now expect the results of research they have funded to be made freely available online as soon as possible. Read more
If you know the academic home of the author, you may find that s/he has been able to put a copy in the institutional repository of that university. This is not always possible - not possible quickly - because of restrictions imposed by the publishers of the law journal in which the article was officially published.
Some examples of UK institutional repositories:
Major collections of working papers (in English) relating to law and related disciplines: