If you need to research a particular area of the law, an up to date textbook on the subject is a good place to start. You can develop your research further by using legal databases.
Halsbury's Laws of England is available online as part of the Lexis Library database. It can be used as a starting point for research on any legal topic, and includes references to relevant legislation and cases, as well as commentary. Halsbury's Laws is also available in the LAWS sequence in Western Bank Library and is continually updated.
Insight is part of the Westlaw UK database. It is a developing online legal encyclopaedia that aims to provide a comprehensive statement of the law in the United Kingdom, delivered via a topic-based interface.