Premiership Rugby is to look into the process in which Northampton’s Wales wing George North suffered his latest head injury.

North landed awkwardly on his right side and his head made fleeting contact with the ground on Saturday in a first-half collision with Leicester wing Adam Thompstone, who was shown the yellow card.

Although television pictures suggested North may have been knocked out in the incident, he was allowed to rejoin the game five minutes later after he had been given a mandatory Head Injury Assessment by Northampton’s medical staff.