Kingston Council has been criticised in a report examining how two troubled teenagers were left with potentially life threatening injuries after a triple stabbing in Chessington.

The serious case review, published today, outlines how police and social workers, focused on "procedures not outcomes" for the boys, who had both been involved in previous criminal activity and had spent time in prison.

The two teenagers tried to rob a drug dealer near Sir Francis Barker recreation ground in Chessington on May 30 last year hours after walking out of a courtroom with a community sentence for another offence.

While the report says the incident may have been unavoidable, it criticises the borough's multi-agency working which allowed the pair to each skip more than a year of school.

It also says no-one recognised "that the escalation of their criminal activity could mean that they were at greater risk of significant harm".

It also questions the effectiveness of the police's missing person procedures and stop and search tactics.

The pair - known throughout the report as Tom and Vic - were stabbed during a fight in Leatherhead Road on May 30, 2012. A third person was also injured and all three were arrested. Tom and Vic later pleaded guilty to affray.

A serious case review was agreed because Tom was living in foster care and there had been "intensive involvement by a number of agencies with both young men".

The report says: "It is not clear whether it was possible to prevent these young men from sustaining potentially life-threatening injuries as they were both involved in risky anti-social behaviour and criminal activities and might not have ceased these activities.

"The review has identified, however, that professionals were insufficiently aware of the implications of this behaviour and specifically did not identify that the escalation of their criminal activities could mean that they were at greater risk of significant harm."

It also called the failure to provide formal education to the teenagers "unacceptable".

Deborah Lightfoot, the newly appointed chair of the Kingston Local Safeguarding Children's Board, which commissioned the report, said: "The case is unusual in that it involves two young men who were simultaneously victims and perpetrators of crime.

"The events probably could not have been avoided but there were significant issues for us to learn lessons from and improve services.

"Professionals were not sufficiently aware of the implications of this anti-social behaviour. We were also looking at the individual and not looking at the impact of the two young men together.

"We are using this serious case review to ensure that across the local partnership the front line professionals are aware of these sorts of issues."

Kingston police borough commander Glen Tunstall, also newly appointed, said: "Stop and search is an effective tool. Had we done one more stop and search before they got to that location we wouldn’t be here.

“It is unclear whether we could have stopped these events from occurring."

Kingston's Conservative leader councillor Howard Jones said: “All in all I thought it was a pretty reasonable report.

"If there is a serious incident like this they have a duty to look in to it - it looks like they're getting their act together."

Other Kingston serious case reviews

Feb 2013 - A paedophile sentenced to 18 years in prison for raping his own children was allowed to continue because of mistakes by various public bodies.