As a police crackdown and heavy rain prevented a fifth night of chaos, Cameron told an emergency session of parliament he would give police extra powers including the ability to order youths to remove face coverings.

Cameron added that a year before London hosts the 2012 Olympics, Britain needed to show a more positive face to the world after the riots in which four people have died and dozens of buildings have been torched.

"We will not stop until this mindless violence and thuggery is defeated and law and order is fully restored on all our streets," he told lawmakers.

Anyone whose property was damaged would be compensated, Cameron added.

Britain is still reeling after four of the worst nights of rioting for decades, which started in London then spread to other cities including Manchester and Birmingham.

The riots were sparked by anger over the shooting by police of a 29-year-old man, Mark Duggan, in the deprived north London district of Tottenham.

AFP