Looking at the lengthy 'Human Rights Joint Committee - Seventh Report
Demonstrating respect for rights? A human rights approach to policing
protest', recently published.

 http://www.publications.parliament.uk/pa/jt200809/jtselect/jtrights/47/4702.htm

The section on SOCPA states, "Sections 132 to 138 of SOCPA should be
repealed." Now this just happens to include section 137 'Loudspeakers in
designated area' which was used by police against CM sound systems since
2005 and up until recently when the police stopped accompanying the rides
following the successful CM appeal to the Law Lords.

 http://www.publications.parliament.uk/pa/jt200809/jtselect/jtrights/47/4708.htm#a30

But it goes on to say, "The Home Office and parliamentary authorities
should work together to develop a coherent framework for managing noise
from protest, with a statutory power to move an individual or confiscate
sound equipment as a minimum requirement."

Hopefully this will not apply to mobile sound systems, especially as the
police never seemed to use the loudspeaker law against car, van or bus sound systems, but just against CM and static protests.

 http://www.criticalmasslondon.org.uk/socpasounds.html