There are many different paths to careers in law. Some people choose to study law as their first degree at university, others study something else and then convert to law afterwards...
Law firms do not just employ law graduates, they employ people who have studied all sorts of different things.
Most universities that offer law degrees, including UCL, do not specify any particular subjects at GCSE or A Level (except some fairly standard competence in maths and English). To see the entry requirements for UCL’s law degree please see our website.
You can also use the UCAS website to find all the universities in the UK that offer law degrees, and compare their entry requirements.
If you plan to study something else and then convert to a law career, then our main advice is to pick a subject that you enjoy! If you know what subject you want to study at university then you can pick your GCSE and A Level choices around this in the same way – by looking at the subjects universities ask for in their entry requirements for those courses.
If you know for certain exactly the kind of job you want to go into such as a financial/corporate lawyer then you can make a start in researching what employers ask for in those jobs. The UCL Careers Service has an Online Careers Library which contains a wide range of useful websites and other e-resources for career planning. You can search for these by job sectors (such as law).
You can also go straight to the websites of law firms to see what they look for in recruits. A list of some of the top law firms in the UK can be found on Prospects' website.
One final note, which links back to the idea that you can study something else and then convert to law later, around 80% of all graduate jobs (jobs that require you to have a degree) do not specify what subject you should study. Most jobs just want you to have a degree, and it doesn’t matter what that degree is. This means that by studying something you enjoy rather than something you feel you have to study for a certain career, you will have a better time at university and it keeps your options open should you change your mind about your career later.