Former Saracens captain Alistair Hargreaves says the failure to sanction Northampton for their handling of George North's latest head injury a "disgrace".

It is the strongest condemnation yet of the decision by a joint Rugby Football Union and Premiership Rugby investigation not to charge Saints with misconduct for allowing North to resume playing after he appeared to have been knocked unconscious in a league match on December 3.

Two months ago Hargreaves, Saracens' 2015 Aviva Premiership-winning captain, announced his retirement from the game at the age of 30 after suffering five concussions in two years.

Reacting to the findings of the review, which acknowledged that North should not have been allowed to play on but declined to open disciplinary proceedings as Northampton were not wilfully negligent, Hargreaves voiced his anger:

Replays appeared to show that North had been knocked out following an aerial collision with Leicester's Adam Thompstone at Welford Road, yet he passed a head injury assessment (HIA) and resumed playing.

Saints' defence is that not all replay angles of the incident were available at the time of assessment and that the Wales international denied any loss of consciousness, had immediate recall of events and stayed motionless due to concerns for his neck pain.

The Rugby Players Association reacted to the verdict of the investigation by describing the "breakdown in procedure" that enabled North's return to play as a "significant failing", adding that it would have preferred disciplinary action to have been taken.