The former England U21s player went down in a contact situation in a game against Munster last August and suffered what could have been a potentially career-ending injury.

Percival, aged 23, had surgery on the injury at the Radcliffe Infirmary in Oxford before starting an extensive rehabilitation programme which concluded with testing at former England rugby physiotherapist Don Gatherer’s clinic in Aylesbury.

Saints medical manager Cliff Eaton said: “James underwent a neck strengthening programme as part of his rehabilitation and when he went for testing, he was shown to have the strongest neck muscles that Don Gatherer’s clinic had ever recorded. We are delighted he is able to resume his rugby career as of today.”

Centre Rhodri Davies, who had surgery for groin instability last season, has also been cleared to resume full training.

Fly-half Luke Myring, who is now four month post shoulder surgery, has been taking part in controlled contact sessions with the physio team and is expected to be fit for the pre-season games.

Mallon and Myrring back in the gym today

Similarly, centre Seamus Mallon, who scored Saints opening try of last season, is also expected to take part in the pre-season friendlies after making exceptional progress following a knee reconstruction.

Flanker Ben Lewitt had an operation on an injured toe five weeks ago and is expected to start running on the beach next week, when the squad travels to Newquay for a pre-season camp.

Centre Neil Starling had to have a second operation on his knee after the original graft failed in the latter stages of his rehabilitation. He will need another year to rehabilitate from his second bout of surgery and will carry out some of his programme at the English Institute of Sport at Northwick Park Hospital in Harrow.

The majority of the squad checked back into Franklin’s Gardens today for fitness testing ahead of their trip to the south-west coast next week.

Ian Vass returned to the Gardens today