James Craig, the former Scotland winger, has become the latest rugby player to reveal that he has developed a serious condition as a direct result of head injuries suffered while playing the sport.

Part of Glasgow sporting royalty Craig was the most successful of four sons of Lisbon Lion Jim who took up the alternative footballing code on attending St Aloysius College.

However having suffered from hallucinations since 1999 he was finally diagnosed as having a bipolar disorder only last year and is in no doubt that his illness which could swing from manic episodes to sustained suicidal tendencies is a direct result of collisions on the rugby field.

“Over the course of my career I had a minimum that I can remember of 15 head injuries,” said Craig.

“Whether that was being fully knocked out or getting a bang on the head and double vision or being hit hard where you get to that point where you’re groggy.

“A lot of the times you don’t own up to these things, you know, you get up and you play on.

“There’s been multiple occasions when that happened and on some occasions you got headaches at the time.

“ I don’t know if it’s the case that you don’t think it would happen to you or you didn’t know much about it but you knew you could get concussed and that there was a possibility you might feel sick afterwards, but apart from that not much else.”

While Bill Beaumont, England’s 1980 Grand Slam winning captain, cited repeated concussions as the reason he quit rugby in the early eighties, Craig – who played for Glasgow and Rotherham before retiring due to a leg injury 11 years ago - says he never received any advice about the potential consequences of head injuries in what were the early days of professional rugby.

“I think there was an ignorance,” he said.

“We knew that if you had a head injury you were three weeks out, but we were never tested in that three weeks. You got back into training gently, but nothing involving testing your motor skills or anything like that.”

The players themselves would down-play symptoms too because of, Craig reckons, a combination of the macho culture prevalent in rugby and fear of the implications for earning power.

“It was definitely about being seen to be hard and the flip side was the selection process of getting picked for Glasgow or Scotland A or Scotland itself,” he said.

“That’s always at the forefront of your mind that if you have had a bang and you’ve managed to keep yourself in the present moment do you own up to it or do you not?”

He has not turned against rugby.

“I don’t regret ever playing rugby and I don’t regret ever being a professional rugby player but I wish I’d taken a bit more care of myself, especially with regards to the head injuries,” he said.

However he is aware that with Rory Lamont, a Scotland winger of more recent vintage, having campaigned vigorously on the subject and other leading players having admitted to suffering serious consequences, it is a burning issue for the sport, not least in light of the huge pay-outs made in the USA to former NFL American Footballers who have suffered similarly as a result of head injuries.

“I think we should have been looked after a bit better than we were but in terms of the players getting together I don’t know… and going the same way as the NFL I’m not entirely sure about that either. That seems to be a real storm over there as far as sport goes,” Craig mused.

“There probably should have been more cognitive tests done for us after being concussed, though.”