http://www.met.police.uk/co/territorial_support.htm
The Special Patrol Group (SPG) was formed in 1965 to provide a centrally based mobile squad for combating particularly serious crime and other policing issues which could not be dealt with by local police.
The convenient presence of a disciplined, well-organised team brought the group into increased use for the policing protests and demonstrations, where their presence came to assume unwanted symbolic significance.
In 1986 the SPG was disbanded and was replaced a year later by the Territorial Support Group.
For those not familiar with why they are in the news: Met suspends G20 footage officerThe Territorial Support Group (TSG) has three main tasks
* Provides an anti-terrorism and domestic extremism capability.
* Provide an immediate response to spontaneous disorder anywhere in London.
* Reducing priority crime.