Depends on the University and the year. This year your looking to spend about 3200-3600 for a good university. At a top one it could cost anything up to nine thousand a year. On top of this you will have to pay for your text books and unfortunately they are ridiculously priced some going as 200 pounds!. If your looking to then go further as a solicitor or a barrister that's another nine to ten thousand for the extra two years but that will probably include your text books.
However don't let the fees put you off its a good career and will pay brilliantly at the end.