After four nights of the worst riots in decades, Britain's capital is quiet but the aftermath of the unrest continues with courts open through the night to deal with 1,200 arrested looters.

Outwardly the rioting is over but concerns continue to mount over the many ethnically segregated districts battered by the rioting as authorities worry about interracial violence that could be started by the past days and nights of violence.

Police have arrested a 32-year old man of Afro-Caribbean descent accused of the death of three young men of Pakistani descent who were killed in Birmingham on Tuesday night when a car crashed into the group of residents who were protecting a local business from looters.

Meanwhile the fallout from the rioting continues as an emergency session of Parliament will be held on Thursday to debate the escalation of violence from the last four days. The initial failure of the police to contain the riots, the perceived absence of political leaders during the worst of the crisis and the cruelty of the attacks that have left four people dead have left a Britain eager to look for someone to blame.

Cameron has taken a tough line against the looters and declared a fightback against those responsible for the widespread destruction.

"We needed a fightback and a fightback is under way," Cameron said in televised statement outside Downing Street after a meeting of the nation's crisis committee on Wednesday.

"There are pockets of our society that are not just broken but, frankly, sick," Cameron said. "When we see children as young as 12 and 13 looting and laughing, when we see the disgusting sight of an injured young man with people pretending to help him while they are robbing him, it is clear there are things that are badly wrong in our society.

"The sight of those young people running down streets, smashing windows, taking property, looting, laughing as they go, the problem of that is a complete lack of responsibility, a lack of proper parenting, a lack of proper upbringing, a lack of proper ethics, a lack of proper morals," he continued. "That is what we need to change. There is no one trigger that can change these things. It's about parenting, it's about discipline in schools, it's about making sure we have a welfare system that does not reward idleness. It is all of those things."

Cameron also added that contingency plans will include using water cannons, used in Northern Ireland but never in Britain. Police had also been authorized to use plastic bullets against rioters.

"We now have in place contingency plans for water cannon to be available at 24 hours' notice," he said.

Even as Cameron promised tougher measures against future rioters, rising tensions between ethnic groups could signal a new wave of violence.

Turkish groups in Hackney and other London neighborhoods have armed themselves with baseball bats and other weapons to protect their homes and businesses. Muslim groups have vowed to fight back against any groups that threatened their neighborhood. In Birmingham, a large police presence has moved into the district of Winson Green, the neighborhood where the three Pakistani men were killed by the driver.

A police spokesman had said earlier that the car had been driven deliberately into the group of young men protecting a local gas station from looters.

"They lost their lives for other people, doing the job of the police," said witness Mohammed Shakiel.

"They weren't standing outside a mosque, a temple, a synagogue or a church - they were standing outside shops where everybody goes. They were protecting the community."

Tariq Jahan, father of one of the young men asked for calm from the South Asian community against the car's driver and occupant who are reported to be black.

"This is not a race issue. The family has received messages of sympathy and support from all parts of the community - all races, all faiths and backgrounds."