London: A teenage boy has been charged with murdering a pensioner, one of the five people killed during England's worst riots in decades, as intelligence agency MI5 joined the hunt for rioters to help decode encrypted messages on BlackBerry used by looters to coordinate their actions.

68-year-old Richard Bowes was attacked in Ealing, west London, on August 8. He died of head injuries three days later.

Metropolitan Police charged a 16-year-old boy, who was not identified, with murdering him after it was authorised by the Crown Prosecution Service last night to press charges against him.

Meanwhile, the MI5 and the electronic interception centre GCHQ have been asked by the government to track down rioters and their messages that led to coordinated attacks in various parts of London and elsewhere, Guardian reported on Tuesday.

The move represents a change as officially MI5 is tasked with ensuring the national security of the United Kingdom from terrorist threats, weapons of mass destruction, and espionage.

Deputy Premier Nick Clegg separately said an independent communities and victims panel will be set up to hear from those affected by the riots. It would not be a full public inquiry, but would report back to all three main party leaders.

The rioters, who were not jailed, would have to take part in community payback schemes in the areas and "look their victims in the eye".

Home Secretary Theresa May told police officers that they would have political backing to use tough tactics to deal with rioting, as new guidelines were issued to forces. May said officers were criticised for being "too tough" but would always have her backing if they acted "within reason and the law".

One of the measures being considered is imposing "general curfew" in specific areas, May said.

Meanwhile, the city of London has announced a 50 million pounds fund to help make major long term improvements to the capital's town centres and high streets damaged by the recent disturbances.

"We have always recognised the importance of improving London's town centres and clearly after the destruction caused by the recent events across the city this is a bigger challenge than ever", Boris Johnson, mayor of London, said in a statement.

A key difficulty for law enforcers last week was cracking the high level of encryption on the BBM system. BBM is a pin-protected instant message system that is only accessible to BlackBerry users.

BlackBerry maker RIM had said it will actively cooperate with law enforcement as they investigate those behind the unrest.

The report said the police struggled to access the BBM network last week, though some who were sent messages planning violence were so outraged they passed them on to law enforcement agencies.

In a speech, the Deputy Prime Minister said those involved must be both punished and "made to change their ways". He said, "That's why those people who behaved so despicably last week should have to look their victims in the eye.

They should have to see for themselves the consequences of their actions and they should be put to work cleaning up the damage and destruction they have caused so they don't do it again." May had been told that some officers had felt "because of criticism of police tactics in the past" police had felt "damned if they do and damned if they don't".

She told police officers, "As long as you act within reason and the law, I will never damn you if you do."

Clegg announced that the victims' panel would be chaired by an independent figure with knowledge of some of the issues concerned and would report back in six to nine months.

He said he wanted to break the "dismal cycle of repeat crime" which was reflected in the fact that 60 per cent or more of the adults in court because of last week's disturbances had previous convictions or were known to the police.