The teenager who killed pensioner Richard Mannington Bowes during the summer riots has been sentenced to eight years' detention.
Darrell Desuze, 17, punched the elderly man to the ground as disturbances swept the country on August 8 last year.
Mr Bowes, who had been trying to put out a fire in a dustbin near his home in Ealing, west London, suffered brain damage and died three days later in hospital.
Desuze's mother Lavinia was jailed for 18 months at the same court for perverting the course of justice by cutting up his clothes. Desuze, who could be named after an order banning his identification was lifted by a judge, admitted manslaughter last month.
Mr Justice Saunders said he took into account the teenager's previous guilty pleas to violent disorder and burglary at William Hill, Tesco Express, Blockbusters and Fatboys Thai restaurant on August 8, when passing sentence.
The judge said Desuze "played a full part in the violence" and could be seen on CCTV smashing windows, looting shops, throwing missiles at police and wheeling rubbish bins into the street so they could be set on fire.
He said most people were afraid to go out, and those caught up in the violence would have been "terrified".
"One person who was not terrified to be out and was not prepared to be forced off the streets was Richard Mannington Bowes."
He said CCTV showed the pensioner moving among the riots and trying to prevent fires started in the bins from spreading.
"The death of Mr Bowes was pointless and unnecessary and it became for the public one of the most, if not the most, shocking event of the riots in London," he said.