The Prime Minister said water cannon – until now only ever seen in the UK in Ulster – will be available at 24 hours notice to deal with the “despicable violence” being carried out in cities across the country.

And in a sign that other more draconian crowd control measures will now be at the disposal of the police he said: “We will do whatever is necessary. Nothing is off the table.”

In his strongest comments yet on the perpetrators of the violence, Mr Cameron said: “There are pockets of our society that are not only broken, but frankly sick…It is a complete lack of responsibility in parts of our society, people allowed to feel that the world owes them something.”