Jamie Cudmore is not a man who has spent his life in need of protection. At 6ft 6in and close to 19st, the 38-year-old former lumberjack has spent more time dishing out pain to others, first as a teenage tearaway before channelling his physical prowess as one of professional rugby’s most feared second-row enforcers.

With a disciplinary record as long as one of his Popeye-shaped forearms and a face battered and scarred by almost two decades of life at professional rugby’s coal-face, Cudmore is no one’s idea of a soft touch.

But he is worried. And so is his wife Jen. Worried about what the future might hold after repeated head knocks through his career and worried about the past. They are angry too, believing they have been failed by a system intended to protect players but which is still open to manipulation.

Jamie Cudmore is worried about the future after suffering multiple head knocks in his career

Cudmore and his wife Jen are fighting to see an improvement in concussion education

Their concern stems from when Cudmore clashed heads with Billy Vunipola last year

Their concern revolves around an incident in last year’s Champions Cup semi-final against Saracens when Cudmore — playing for French Top 14 giants Clermont Auvergne — clashed heads with a similarly immovable object in Billy Vunipola, sparking a chain of events which could have huge ramifications for World Rugby’s much scrutinised Head Injury Assessment (HIA) protocol as well as Clermont’s medical staff and potentially Cudmore’s future mental health.

‘There was a huge head contact with Billy and myself going head to head at a ruck,’ said Cudmore.

‘It’s an accident of rugby, two guys arriving at the same time at the same height. We were both on our hands and knees and I remember saying, “Jeez, that was a good one”.

‘Billy said, “We’ll be good, bro”, and sort of staggered off. I remember being on all fours and figured I might as well wait for the docs to come on and maybe go off for a bit of blood. At the same time I was just trying to recover because I knew I’d taken a really big knock.’

Cudmore should have been removed from the field but was allowed to continue playing

Far from being permanently removed from the field — as he should have been under World Rugby’s concussion protocols — Cudmore was examined by Clermont’s doctors, failed the HIA test but was somehow allowed to return to action.

‘When I got back to the changing room they started to stitch me up and then after that they put me through the HIA. The usual questions, remembering five or six words and answering them back to the doc.

‘I had no chance. I probably remembered one of the words and I remember clear as day, I can see his face now, saying, “No, you’re done . . . c’est fini”.

‘I was distraught. It was a semi-final and I wanted to be on the field. You work all year to be in those games. I was upset. The doc could see I was upset and told me to relax, take my boots off and get in the shower.

'So I walked back into the changing room and I hadn’t even got my boot off when I heard the door open and the doc come back in and say, “Jamie, Jamie, how are you? Sebby [second row partner Sebastien Vahaamahina] is not good. Can you come back on? You gotta come back on”. I was like, “Yeah, sweet”, and tied my lace and went straight back out.’

The Oyonnax second-row had no idea of the risk he was taking when he returned to the pitch

At the time, Cudmore had no idea of the risk he was taking by returning to the field having already sustained a potentially serious head injury. He had not heard of second-impact syndrome, which four years earlier had killed 14-year-old Ulster schoolboy Ben Robinson and is the primary reason any person who has suffered a suspected concussion is supposed to stop playing immediately and seek medical advice.

It is precisely the reason the Cudmores have embarked on their mission to improve concussion education while raising funds to increase research through their Rugby Safety Network.

The fall-out from the massive legal pay-out to former NFL stars with early on-set dementia linked to repetitive head injuries could take decades to play out as other sports attempt to safeguard participants and prevent a decline in participation.

Rugby union has acted more decisively than most — arguably because its problem is greatest — but while Aviva Premiership clubs have wised up in recent times, their French Top 14 counterparts appear years behind.

Despite the injury, Clermont's doctors gave Cudmore permission to play just two weeks later

In Cudmore’s case, Clermont’s doctors should have known better. But, apparently caught up in the moment and with lines blurred between patient, player, employer and team, allowed him to return before permitting him to play in the final at Twickenham two weeks later against Toulon when — with Jen watching on distraught in the crowd — he suffered yet another potentially fatal concussion.

‘Two or three minutes into the game I hit Chris Masoe and their other prop behind him at the same time and was just sparked straight out,’ says Cudmore. ‘It was a normal tackle leading with the shoulder. There was no contact with my head. But the force of the impact sparked me straight out. My body just went limp.

‘I went off, did the HIA and a new doc we had figured everything was all right and I went back on. Towards the end of the game I had a clash of heads with Juan Smith and cut myself. I went off and started vomiting in the changing room. I didn’t know about second impact syndrome. I didn’t know I could have died.

‘[Clermont wing] Benson Stanley was in there as well. I remember talking to him after and he asked me how I kept on playing. I said I didn’t know but I just kept going. He also asked me, “How could the doc let you back on?”

Cudmore admitted that he worries about the future impact the blows will have on him

‘I definitely worry about the future. I don’t want to be one of those guys who is 65 but can’t remember anything.’

It was the moment Jen lost all faith in Clermont’s medics.

‘I was in the stands with Jamie’s dad, Richard,’ she said. ‘We’d had a week of hell after the Saracens game with Jamie not able to sleep and constantly telling me he had this cloudy, cotton sound in his head. I knew it was not normal, but had to rely on the doctors.

‘For the game in London we had to rely on the doctors to take care of him. We saw Jamie go down in the final and instantly wondered if he would go off. He did, which was good. But then he came back on and that’s when I just lost it. I’d had enough. I was freaking out, standing up and everyone else was telling me to sit down. They were watching the game and I was freaking out because my husband was not well.

‘Before we knew it he was down on his hands and knees again. I was shouting, “Richard, I need to go”, and he was saying I needed to have faith in the medical staff. But it had been going on for two weeks and it was starting to look to me as if they were trying to kill my husband for a trophy.’

Cudmore's wife Jen thought it looked like 'they were trying to kill my husband for a trophy'

Incredibly, Cudmore finished the game but after blacking out in training the following week he was mercifully, belatedly, stood down. It took him three months to recover — the first few weeks spent largely in a darkened room as he battled post-concussion symptoms including mood swings, sensitivity to light, lethargy and nausea.

Despite Jen and others urging him to retire for fear of permanent damage, Cudmore — who grew up in Squamish, British Columbia — went on to play for Canada in last year’s World Cup before being branded a ‘traitor’ by Clermont when he wrote a letter to the club raising grave concerns over his medical treatment the previous season.

As they look to build a legal case against his former club — he now plays for Oyonnax in France — Cudmore has been told no video footage exists from within the Twickenham changing room while a formal complaint made to European Professional Club Rugby, the organisers of the Champions Cup, drew a response from director general Vincent Gaillard pointing out the HIA was a World Rugby trial and therefore not under his body’s jurisdiction.

It is an unholy mess and — as in the case of former Sale scrum-half Cillian Willis, who is suing former employers for medical negligence for a mishandled concussion in 2013 — is destined for the courts.

Jen, who has two children with Jamie, insisted that she will not let the issue slide

Jen, the mother of Cudmore’s two children, Maelle, 6, and Jackson, 4, insists she will not give up the fight.

‘For 10 years Jamie mentally and physically exhausted himself for Clermont but instead of supporting his work with the foundation they accused him of being a traitor and just trying to create a buzz,’ she said.

‘They think it’s some kind of joke. Do you think we have the time and energy to do that?

‘I see a bunch of things that are wrong in terms of corporate liability, transparency, accountability. There are no medical records, no video footage. They think we’re going to go away. That p***es me off even more. There’s a whole bunch of things that are wrong.

‘Who is accountable for what’s happened? By the looks of it nobody. It seems to me that everyone’s got their backs protected and no one’s looking out for the players.’