The two main publishers are:

Butterworths
Sweet & Maxwell

Other legal publishers include:

Aspen Publishers
BRILL Academic Publishers (range of titles on Middle East & Islamic law)
Cambridge University Press
Cavendish
CCH
EU Bookshop
Gee Publishing
Hart
IDS
ILI
Informa Law
Institute of Chartered Secretaries & Administrators
Jordans
Juris Publishing (International law publications)
Kluwer Law International
Law Society Gazette
Legalease
Oxford University Press
PLC Magazine
Stationery Office - now the Office of Public Sector Information (opsi)
Tottel
Tru-est Publishing Group
John Wiley

Legal bookshops include:

Books Etc
Hammicks Legal Bookshops
Lambs Bookshop
Wildy & Sons Ltd

UK Law Journals Directory

A list of UK law journals published in both electronic and paper form. This site has been developed by the electronic law journals team at the University of Warwick.

http://elj.warwick.ac.uk/juk/

Legal Information Publications Database

Bibliographic details of recent books and periodical articles relevant to law librarians and legal information specialists, published from January 2001 onwards.

http://ials.sas.ac.uk/library/acqlist/acqlist.htm