Nooragha Zadran, 18, said he was only five when both of his parents were killed in the Afghanistan when a bomb struck their home.

He was left to fend for his younger brother by begging on the streets. He left the boy in a playground and never found him again.

He arrived in Britain as a young boy and had been in the care of social services since.

But during the disorder that blighted Britain last August he threw rocks at police and lit the rag that was used to set fire to a parked car in Lewisham, southeast London, a court heard.

However he walked free from court today after Judge Nigel Seed QC described his case as "exceptional."

"No other defendant will have appeared in front of the courts in such circumstances. That is why you are not being sentenced to two to three years in prison," he said.

Inner London Crown Court heard that Zadran, who works at a mobile phone kiosk in Lewisham, is 'extremely vulnerable' and prone to exploitation as a result of his childhood.

He also suffers from severe post traumatic stress disorder, stress and anxiety, and was handed a 12 months sentence, suspended for two years.

The judge said: "I take into account the fact that at an early age you were living in war torn Afghanistan where you would have been exposed to violence everyday.

"The family home was bombed and the explosion killed your mother and father, leaving you and your siblings orphans.

"You were left to beg because of your destitution.

"You left your younger brother in a playground to try and beg, and he then disappeared and all this happened before you were ten years old.

"You suffered from post traumatic stress disorder, and a particularly complex form of post traumatic stress disorder, which is very serious and makes you vulnerable to exploitation, and unable to think clearly."

Neil Griffin, defending had told the court that he had got involved in "half an hour of madness" and he wished "he could turn the clock back."

Prosecutor Gordon Carse told the court that Zadran had been caught after a media appeal in December, and was spotted in Lewisham town centre in his mobile phone kiosk.

"There was a group of young men, who had began instigating attacks on the police, throwing things at them," he said.

"On CCTV the defendant is seen breaking up a brick and taking the pieces and throwing it at them.

"The group moves away and he is with them. There is a blue Citroen vehicle which is alight, and the defendant lights a cloth from it and goes toward a red Vauxhall Tigra.

"There is a basis of plea that he did not set fire to the car, but left the burning cloth near it, knowing others would. The Vauxhall Tigra is then consumed by flames."

Zadran was ordered to pay £2,000 to the owner of the car, and required to attend mental health treatment as part of his sentence.

Zadran, of Rotherhithe, southeast London, admitted one count of violent disorder and arson.