Adam Khan Ahmadzai was described by police as a ringleader in the Croydon riots.
The 20-year-old from Feltham pleaded guilty to 10 offences, including one count of violent disorder, three counts of burglary, four robberies and two counts of criminal damage.
In January he was jailed for four years, but four months later he had his sentence increased, after Attorney General Dominic Grieve referred the case to the Court of Appeal, on the basis his original sentence was unduly lenient.
Ahmadzai's sentence was nearly doubled after the Attorney General told the court Ahmadzai had committed an "extraordinary list of crimes."
He said: "He led an attack on a police line, robbed a bus driver who he had forced to halt, armed himself and ransacked a shop.
"He repeatedly attacked and mugged a terrified man at a cash machine, acting as if pushing a gun into his neck and led a gang into a supermarket."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here