Police in London flooded the streets on Friday in a move to prevent a repeat of England's worst riots in decades, which left city neighbourhoods smouldering and five people dead.
The number of officers in the British capital was more than doubled to 16,000 earlier this week, and Home Secretary Theresa May said the extra police would stay in place until further notice amid concerns violence could flare up this weekend.
Britain has had two quiet days following four nights of rioting and looting, which led to 1,500 arrests across the country, but politicians and police were taking no chances.
Speaking on a visit to a Sony-owned distribution centre in north London which was torched during the riots, May said: "We will be sustaining the numbers for a period of time.
"We have had some quieter nights but we are not complacent about that."
Police meanwhile said a 68-year-old man died in hospital late Thursday from injuries sustained confronting looters in west London, becoming the fifth person killed in the violence.
Police have arrested a 22-year-old man on suspicion of the murder of Richard Mannington Bowes who was set upon in the affluent London suburb of Ealing Monday as he tried to put out a fire started by a gang of youths.
The other victims of the unrest were three men in Birmingham who were run over as they defended local businesses, and a man in Croydon, south London, who was shot.
The attack on Mannington Bowes "was a brutal incident that resulted in the senseless killing of an innocent man," said Detective Chief Inspector John McFarlane of London's Metropolitan Police.
Inquests were due to open Friday into the deaths in Birmingham, England's second city, which saw three young men of South Asian origin mown down by a car as they stood guard against looters outside a petrol station.
As fears of new violence remained high, a row escalated between police and politicians as both sides sought to deflect blame for the crisis.
The police have been criticised for their reluctance to crack down hard on the first riot in the north London district of Tottenham on Saturday. Critics say the cautious approach encouraged unrest to spread across the capital and then to other English cities.
In an emergency session of parliament Thursday, Prime Minister David Cameron said police would be given extra powers to prevent future trouble but also voiced criticism of their tactics.
Cameron told lawmakers the police had initially "treated the situation too much as a public order issue -- rather than essentially one of crime."
May, Britain's interior minister, has also said there were not enough officers on duty on Monday, the worst night of the unrest during which police in London arrested more than 300 people.
But senior officers hit back Friday in rare public attacks on political leaders, who last year introduced funding cuts to police forces across Britain as part of a package of austerity measures.
Tim Godwin, the acting head of the Metropolitan Police, pointedly noted that "people will always make comments who weren't there", and defended the policing of the riots in which dozens of officers were injured.
He said in the face of "unprecedented scenes", his force had "some of the best commanders that we have seen in the world... that showed great restraint as well as great courage."
Cameron and May were on holiday when the riots broke out, and returned early this week to take control, but senior officer Hugh Orde, who represents Britain's police chiefs, said their presence was an "irrelevance".
He also criticised a claim by May that she had ordered police forces across the country to cancel all holiday, saying that she "has no power whatsoever to order the cancellation of police leave."
Courts across the country, which have been working round the clock to process cases, faced another busy day on Friday to deal with the more than 500 people charged over the disturbances.
Among those hauled before the courts on Thursday was an 18-year-old girl from London who is a youth ambassador for the 2012 London Olympics. She was accused of throwing bricks at police and stealing from shops.