David Cameron has described the Oxfordshire paedophile ring case as "absolutely appalling" and "shocking".
The Prime Minister, whose constituency is in the county, said police, social services and the council would have to answer "searching questions".
"There's no doubt that first of all it's good that those who did wrong have been tried and found guilty and are going to be properly punished," Mr Cameron told reporters on his trip to the US.
"That is step one. But step two is obviously going to be the authorities - the police, social services, county council - everyone's going to have to ask some very searching questions about how this was allowed to continue for so long, and I know they are already doing that."
All the victims- some just 11 years old - were vulnerable children in care, and supposedly being looked after by Oxfordshire County Council. So what went wrong - why were they failed so badly? We talked to the leader of Oxfordshire County Council, Ian Hudspeth.
Throughout the Operation Bullfinch trial, Thames Valley Police have insisted that race and religion was NOT an issue....that the men did not see young white girls in care as easy targets. Some of the defendants were born in Oxford and grew up there.
Our reporter, Penny Silvester, looks now at the reaction in the city to the trial and its implications for all communities.
Road to ruin for young girls - controlled by evil gang
They were targeted because they were the most vulnerable….. young girls drawn into a world of sexual abuse, violence and drugs. Reshma Rumsey reports on the background to the cruel abuse in the Oxford area.
Nine men accused of nearly 50 crimes against young girls in the Thames Valley today heard their fate. After nearly 17 weeks an Old Bailey jury today found seven of them guilty on charges ranging from abusing children to rape. Two were acquitted. Phil Hornby introduces our coverage.