The shift in focus away from counter-espionage work comes the day before the Criminal Justice Bill becomes law, giving the police greater powers to prevent demonstrations, raves and anti-hunt protests.
A further sign of changing security priorities, brought on by the end of the Cold War and of IRA violence, came with the announcement that up to 500 jobs are to go over three years at the Government's GCHQ electronic intelligence gathering centre in Cheltenham.
Every police force in the country has a Special Branch unit. Of the approximately 2,000 officers in England, Scotland and Wales, more than 400 work at Scotland Yard.
The Home Office and Scottish Office stressed in the updated guidelines published yesterday that gathering and analysing information on terrorist threats remained the top priority for Special Branch.
But the report, which replaces the 1984 guidelines, put greater emphasis on Special Branch collecting intelligence about animal rights extremists and public disorder. It said the police ``need accurate assessments of the public order implications of events such as marches and demonstrations'', and added that Special Branch officers are usually responsible ``for gathering intelligence on animal rights extremist activity, and seeking to prevent attacks on persons and property targeted by such extremists''.
Special Branch officers were used to monitor last month's Criminal Justice Bill rally in London, which was followed by running battles between protesters and the police.
The Branch is responsible for gathering intelligence about threats to national security, particularly terrorism and sabotage, providing armed protection for VIPs, gathering information about offences connected with firearms and explosives and preventing the spread of information about nuclear and chemical weapons. It also carries out surveillance at ports and airports and makes inquiries about immigration and naturalisation.
Although the new guidelines were drawn up in July - before the IRA ceasefire - a security source said counter-terrorism would remain the main focus of the Special Branch work. Overall control of the gathering of intelligence against the IRA was passed to MI5 in 1992.
Subversion and foreign spies are regarded as a ``much reduced threat'', the guidelines say.
GCHQ job cuts, page 3