usually you'll need to have at least worked as a legal secretary to qualify to to become an ILEX without a degree.
Alternatively, if you do have a degree in any subject, you could take your CPE/GDL (Graduate Diploma in Law), which will effectively convert you into a Law Graduate.
Even with this, or with a proper Law degree, you'd still need to take your LPC to practice (Legal Practice Certificate).
Try picking up a copy of Lex magazine for pretty comprehensive info on all sorts of legal courses and general law profession issues. They also provide a UCAS-type guide, which you should be able to get from any careers office. Also, why not take a look at doctorjob.com for more law career links.
Hope that helps!