Barry O'Driscoll is looking forward to the weekend. The Cheshire-based doctor is heading to Dublin to attend a testimonial event for his nephew, Irish legend Brian O'Driscoll.
But Barry is also a troubled man.
For 15 years the former Ireland full-back has been one of rugby union's insiders, and as a respected expert he sat on the International Rugby Board (IRB) medical committee.
But he is now at loggerheads with the game he loves over the issue of concussion, and has resigned in protest at the decision to trial a new protocol for dealing with head injuries, the Pitch-Side Concussion Assessment (PSCA).
Under the previous IRB approach, any player suspected of suffering from concussion had to leave the pitch and take a week off, a period already reduced from three weeks under an earlier rule. The new guidelines say a player can return to the game just five minutes after the injury, providing a medical inspection clears him of concussion.
"For someone with suspected concussion, all the top scientists say you take them off and watch them that night," says O'Driscoll, who played in the 1971 Five Nations Championship.
"If they incorporate the 'five-minute rule' I think you're putting people with brain damage back on the field, and the arena they're going back into is brutal.
"The game has changed since I played. It's now a big commercial sport, so what's important is to get the spectators in, get the television in. They love the big hits.
"The players have said 'well, we know we're guinea pigs, but that's the deal'. It's our job not to make them guinea pigs in an experiment like this."
According to Rugby Football Union data, concussion is the most common injury in the professional game, with 5.1 instances for every 1,000 hours of rugby played.
Players are now on average more than a stone heavier (7.2kg) than they were 20 years ago, and the force of their collisions can be the equivalent of what the body experiences in a car crash.
Until last year Nic Berry was one of O'Driscoll's "guinea pigs". A man who decided playing rugby for a living was worth the risk of occasionally getting his bell rung.
Except it was not occasionally. Two seasons ago he suffered nine concussions playing scrum-half for English Premiership team Wasps.
"I could take a knock, and know that I had taken a knock - I'd have blurred vision, and be a bit disorientated," says the 29-year-old Australian.
"But if you could keep up with play, you would probably continue. The bad ones you don't remember, though, you don't get up."
Berry was eventually forced to retire when he failed to get up from a tackle in Wasps' season-opener against Harlequins in front of 60,000 fans at Twickenham. He wanted to carry on but a neurologist refused to pass him fit.
"You would finish games and you wouldn't remember the score, or how you played," he adds.
"I knew it wasn't normal, but all my tests were saying I hadn't suffered any permanent damage yet, so I took confidence from that.
"But I look back now and it's plain to see, a bloke who can't stand up straight probably shouldn't be playing.
"I don't hold any resentment to those coaches, or the medical staff, they were following the protocol. And rugby players have got pressures like anyone else - families and mortgages. That probably led to a few instances when I shouldn't have played."
O'Driscoll understands this. He knows these competitors do not want to leave the game, as was witnessed by millions when a groggy George Smith returned to field in the deciding Lions Test this summer, or when his nephew Brian got "dinged" and played on in the Six Nations against Italy.
His anger is directed at the authorities. He believes the IRB's approach to concussion is, in keeping with the symptoms, "confused and contradictory".
"It gives everyone the impression they don't really know what they're doing. It's an awful message to send out to players and parents," he adds.
His prescription for rugby is to err on the side of caution: anyone suspected of concussion sits out for a mandatory week.
For its part, the IRB says player welfare is a priority. It claims the PSCA is supported by experts and the players, and says it is working.
"Prior to the PSCA triage tool, players were being assessed on the field by team medics under considerable pressure in a match environment," an IRB spokesman said.
"Data suggests that 56% of players with a post-match confirmed concussion returned to the field under the previous protocol. In the first year of the PSCA trial that figure has dropped to 13%."
The IRB also said referees have been asked to crack down on deliberate hits to the head, and an age-specific approach is being taken to when a player is ready to return. Younger, more vulnerable, players must sit out longer than a week.
O'Driscoll is not convinced. For him, if a player is injured enough to warrant a pitch-side assessment, he should be suspected of concussion and withdrawn. Five minutes is not long enough, he says, to assess the extent of any potential brain trauma.
Berry agrees, saying: "If a player can't walk off the field unassisted, he shouldn't be going back on in the next five minutes. I think that's crazy."
This will all sound very familiar to American ears.
Two decades ago, concussions were thought to be an inconvenience in the National Football League - as much of an occupational hazard as a groin strain or broken thumb.
Even a spate of high-profile cases involving icons like Dallas Cowboys quarterback Troy Aikman prompted only a very measured response from gridiron's bosses. They set up the Mild Traumatic Brain Injury Committee and put an arthritis specialist in charge.
Nothing much changed for the next few years. Players got hurt, but most of them sniffed the smelling salts and got back out there; some campaigners raised concerns, but the NFL closed ranks.
And then, in 2002, a forensic neuropathologist called Dr Bennet Omalu took a closer look at the brain of deceased NFL star Mike Webster. What he found shocked him, eventually shocked the league and continues to shock America.
Webster had Chronic Traumatic Encephalopathy (CTE), a degenerative brain disease that had previously only been associated with punch-drunk boxers.
Research has since found the condition in the brains of deceased soldiers, ice hockey players and wrestlers, but Webster was the NFL's first, and while nobody knows the precise cause of CTE, the constant between all recorded cases so far is a history of concussions, or repetitive sub-concussive head injuries.
Webster was an offensive lineman, a man whose job it is to butt heads 1,000 times or more a season. So it is not just the obvious spark outs, and it is not just the games. It is estimated 60% of the NFL's concussions occur in practice.
The symptoms of CTE are terrifying for the afflicted and their families: aggression, dementia, memory loss, an inability to balance. Webster, a four-time Super Bowl winner, died at 50, in pain and confused, looked after by his teenage son.
What happened next has recently been laid bare in a remarkable documentary called "League of Denial: The NFL's Concussion Crisis".
Broadcast in the US on 8 October, the programme outlined another 10 years of mounting evidence, ruined lives, head-in-sand refusals to acknowledge the problem and eventually, at long last, an acceptance of the fact the NFL can and should do more to look after its own.
Two months ago, the NFL agreed a £477m settlement with up to 4,500 former players who had accused the league of misleading them on the dangers of head injuries.
The settlement, which covered compensation, check-ups and grants for research, was made on a no-fault basis. The players' case was not proven, and the NFL's defence that it had never knowingly placed anybody in danger was not challenged.
But the saga has taken some of the shine off the game: grassroots participation is down, politicians have likened the sport's tactics to those of the tobacco industry, and prominent commentators such as Malcolm Gladwell have compared the league's ethics to those of dog-fighting.
This was put to league boss Roger Goodell when he visited London last week.
"We do not mislead our players, and we did not hide things from our players," he said.
"What has happened is that you have seen an advance in medicine. We just know more about the brain now.
"The game isn't bad for you - there are injuries and you need to recover from them, it's like anything.
"What we're trying to do is lead a revolution and say there's a lot more we need to know. That's why we're working with General Electric, and pioneering research with the National Institutes of Health."
Goodell, to be fair, has come a long way from his earlier scepticism of the scale of the problem.
In recent years he has made changes to the game's laws to reduce the likelihood of high-speed impacts, fined and suspended players guilty of violent play, invested in safety initiatives and funded research, much of it with those same campaigners who were at odds with the league for so long.
"Concussions are a global issue, they happen in every sport," Goodell added.
"We're no different, but we are under more scrutiny because of our popularity, and because we've said this is something we think we can make progress on."
He finished by saying the NFL was happy to share its research. Should rugby give them a call?
"We don't have the data on instances of CTE, or other neuro-degenerative disorders, in rugby players, but given that they are likely to suffer multiple concussions it seems reasonable to assume that they are at heightened risk," said Dr Adam Hampshire, a senior lecturer at London's Imperial College.
"These players are putting their bodies on the line for the sport, for their fans, and it looks like they are also putting their minds on the line as well. It behoves the research community to work out how we can minimise those risks."
O'Driscoll agrees with Hampshire on the probable risk, and the need for research.
"There's no proof in rugby yet. We haven't been able to do any autopsies or deep research, but it's the same trauma," he said.
"We have to presume it might be a problem."
It has taken researchers in the US more than a decade to start building a compelling case that links head injuries in sport with serious brain diseases in later life. That work is in its infancy here, but Dr Willie Stewart, a Glasgow-based pathologist, has recently found a link between rugby players and early onset dementia.
And the fact Geoff Parling has been withdrawn from England's team to play Australia on Saturday because of a "mild concussion" suggests the message is getting through.
"While everything inside me as a coach was saying I need my experienced second row on the bench to help us close out the game, the medical information is that he needs a mandatory six-day rest," said England head coach Stuart Lancaster on Thursday.
"You abide by the medical position - gone are the days when we can put player welfare at risk."
Just to emphasise this point, the RFU is hosting a Professional Rugby Concussion Forum at Twickenham next week, with representatives from the professional game and players' union attending.
The IRB is adamant it is not blind to what is happening across the Atlantic, but maintains the sports are different. Rugby players do not launch themselves at each other head-first, emboldened by the illusion of invulnerability that a helmet brings.
But the "big hit" culture of the modern game is forcing rugby's bosses, players and fans to confront head-on some very uncomfortable questions.