Northampton could face a charge of bringing the game into disrepute and a fine over the incident in which George North played on after appearing to be knocked out.

The Northampton and Wales wing, who last year suffered a string of concussions including two in one game against England, landed heavily on his neck following a mid-air tackle by Adam Thompstone which earned the Leicester wing a yellow card on Saturday.

North appeared to be unconscious as he was attended by Northampton medics before being taken from the field for a Head Injury Assessment (HIA), which he passed, then returned to play the rest of the match.

George North appeared to be knocked unconscious during Saturday's clash with Leicester

Northampton wing, pictured injured against Wasps in 2015, has a history of head injuries

North falls to the ground after a collision with team-mate Richard Hibbard last year

Strict Premier Rugby guidelines, backed by World Rugby and the RFU, state that any player even suspected of losing consciousness should be immediately removed from the field, with one World Rugby source confirming to Sportsmail that North should not have been sent for an HIA.

‘I would say there is no doubt he qualified for suspected loss of consciousness,’ the source confirmed. ‘He should not even have undergone an HIA. He should have been removed immediately.’

TV pundit Ugo Monye insists the Wales star should not have been allowed to carry on playing

The incident caused outrage at the time, with former England winger and BT Sport commentator Ugo Monye incensed that the 24-year-old was allowed to play on, apparently in contravention of protocols designed to protect player welfare.

‘For me, unless he’s blanking, he’s unconscious,’ Monye said on commentary. ‘His eyes are shut, his arms are down, for me he’s knocked out. Considering his history, he should not be playing in the second half.’

The fact that North was only off the field for eight minutes, when the allotted time for an HIA and the newly trialled King Devick test is 13 minutes, has also raised doubts about the thoroughness of the assessment. Northampton issued a statement after the game, insisting North had not lost consciousness and the wing indicated on Twitter he had landed on his neck and lay motionless as a precautionary measure only.

However, the incident has caused serious concern among rugby chiefs desperate to protect the sport’s image and reduce the high number of concussions. It was being reviewed by an independent assessor with the power to refer the case to an Untoward Incident Review panel.

Northampton, who were beaten 19-11 by the Tigers, could face a disciplinary charge and fine

The club has issued the following statement regarding George North https://t.co/S5hjeZv6Yp — Northampton Saints 😇 (@SaintsRugby) December 3, 2016

Thanks for all the messages. I am ok. I landed on my neck and was worried about it. Thanks to the medics for checking me out properly. 1/2 — George North (@George_North) December 3, 2016

Whoever's responsible for allowing #georgenorth to continue playing after being KO'd should be fired. @ugomonye — Jacques Burger (@Nabasboer) December 4, 2016

Northampton could be charged in the next 48 hours with misconduct as part of an RFU disciplinary process and be fined for failing in their duty of care to their employee.

‘We are in uncharted water here,’ said one Premier Rugby source. ‘Technically, nothing is out of the question in terms of the disciplinary process.’ Some former players, including former Wales stars Jonathan Davies and Shane Williams, dismissed criticism of the Northampton medics, although former Saracens star Jacques Burger was unequivocal.