The warning is among the updates to the revised Guide to Judicial Conduct, which is intended to assist judges in dealing with difficult ethical problems.
The guide offers "assistance to judges" on conduct issues rather than providing mandatory rules. It sets out principles from which judges can "make their own decisions and so maintain their judicial independence," said Lord Justice Pill, Head of the Judiciary, writing in the foreword.
Although the guide makes it clear that the use of social networking is a matter of "personal choice", judges are explicitly warned about the dangers of providing personal information - including addresses and holiday arrangements – to the websites.
"Posting some information could put your personal safety at risk. For example your address, details of holiday plans and information about your family could be used for criminal purposes. Photographs could enable home addresses or car numbers to be identified," the guide says.
The section on dealing with the media has also been amended to refer to the latest guidance available. Judges should exercise their freedom to talk to the media with "the greatest circumspection", according to the guide, and not air disagreements in the press.
A new section on the Office for Judicial Complaints (OJC), which deals with discipline complaints from members of the public as well as those taking part in court action and legal professionals, has been added. Judges are expected to cooperate with the OJC in the discharge of its functions.
The guide is based around six 'values', which are "designed to provide guidance to judges and to afford the judiciary a framework for regulating judicial conduct".
It provides that judicial independence is a "prerequisite to the rule of law". Judges should be alert to attempts made by others to influence them and should be immune to publicity, the guide says.
Although consultation with colleagues is important, the guide emphasises that a judge is solely responsible for his decisions.
Similarly, judges should avoid any activities outside of their role that would cause a conflict of interest, including political activities.
Judges also cannot sit on cases in which one of the parties is a close family member of personal friend. Friendship with a lawyer on a case is not generally enough of a reason for a judge to be disqualified, however a judge should not sit on a case in which the lawyer is a family member.
The Guide to Judicial Conduct was first published in 2004 and updated in 2008. The latest version was drafted by a working group of judges following consultation with the profession.
Written codes of judicial conduct have become commonplace throughout the world in recent years, according to the guide.
