Angie Bray, MP for Ealing Central and Acton, said policing could be ‘more robust’ but added that it was difficult because officers were ‘damned if they do, damned if they don’t’.

Nonsense. They’re damned if they use violence unnecessarily or use a greater force than required, such as in the case of Mr. Tomlinson or Mr. Menenzes.

She said: ‘Policing is done by consent and we have to decide what level of policing we are prepared to go to. In my personal opinion they could be a lot more robust.’

Policing is done by consent? What nonsense!  It’s done by consent when that works, but when it doesn’t, other methods need to be employed.

It was also unclear if frontline officers were hamstrung as the disorder spread by fears that their actions could further inflame tensions.

…

Last night, several flashpoints in the capital were left completely lawless as Scotland Yard ran out of teams to send out to new troublespots.

Residents questioned why no police officers were available to combat rampant looting as thieves methodically cleared stores.

Groups of shopkeepers and young men were forced to take to the streets to fight off rioters to protect businesses in some areas.

Up to 300 officers were drafted in from the Home Counties to bolster the response but they were overwhelmed by the sheer scale of the fighting.

The relative calm in Dalston was laid at the door of ‘heroic mobs’ of Turkish men standing guard in the high street, one resident said.

In the busy shopping street of Green Street, in Forest Hill, there were reports that 400 young Asian men had chased off up to 150 rioters.

via London riots 2011: Where were police? Shopkeepers mystified as they’re left defenceless | Mail Online.

It seems clear that what works is determined people, even unarmed ones, acting in concert.