A group of more than 185 former rugby players are taking the game's ruling bodies to court for negligence in protecting them against head injuries.
The players, a mix of former professionals and semi-professionals, have issued proceedings against World Rugby, the Rugby Football Union and the Welsh Rugby Union, having been diagnosed with a series of irreversible neurological impairments.
The players' lawyers, Rylands, describe this as "the biggest class action of its kind outside of the USA".
The players have a range of irreversible conditions, including early onset dementia, CTE (chronic traumatic encephalopathy), epilepsy, Parkinson's disease and motor neurone disease.
This month, former Wales captain and Lions forward Ryan Jones became the latest player to reveal that he has early onset dementia and probable CTE, joining former England hooker Steve Thompson and All Blacks prop Carl Hayman, among many others.
Jones told the Sunday Times this month: "I feel like my world is falling apart. I am really scared because I've got three children and three stepchildren and I want to be a fantastic dad.
"I lived 15 years of my life like a superhero and I'm not. I don't know what the future holds.
"I am a product of an environment that is all about process and human performance. I'm not able to perform like I could, and I just want to lead a happy, healthy, normal life.
"I feel that's been taken away and there's nothing I can do. I can't train harder, I can't play the referee, I don't know what the rules of the game are any more."
The players believe the governing bodies were negligent and their permanent injuries were caused by repetitive concussive and subconcussive blows.
A spotlight was shone on the issue in December 2020, when Thompson told his story. At that stage, a pre-action letter of claim was issued to the governing bodies on behalf of a group of nine players. That number has now swelled.
A statement from Rylands read: "We are seeing the same worrying symptoms in numerous cases across both codes of rugby. These symptoms include chronic depression, aggression, significant memory loss, incontinence, drug and alcohol addiction, and, in some cases, suicide attempts.
"This claim isn't just about financial compensation — it is also about making the game safer and ensuring current and former players get tested, so that if they are suffering a brain injury they can get the clinical help they need.
"The players we represent love the game. We aim to challenge the current perceptions of the governing bodies, to reach a point where they accept the connection between repetitive blows to the head and permanent neurological injury and to take steps to protect players and support those injured."
Rylands are also working on a "separate but similar potential claim" with 75 rugby league players against the Rugby Football League.