Former England rugby star Steve Thompson has revealed he has dementia and cannot remember being involved in the World Cup triumph of 2003.

Now he, and a group of fellow ex internationals, are planning legal action for negligence against the rugby authorities over brain injuries they have suffered.

The ‘test group’ is made up of eight players, including ex-Wales star Alix Popham and former England player Michael Lipman, who have all been diagnosed with early dementia and probable CTE (chronic traumatic encephalopathy). 

The planned action is against World Rugby, the Rugby Football Union and the Welsh Rugby Union, for ‘failure to protect (the claimants) from the risks caused by concussions’.

Thompson, 42, told The Guardian: "I can't remember any of those games. It's frightening. It's like I'm watching the game with England playing and I can see me there, but I wasn't there, because it's not me.

"It's just bizarre. People talk about stories, and since the World Cup I've talked to the lads that were there, and you pick up stories, and then you can talk about it, but it's not me being there, it's not me doing it, because it's just gone."

It is the first legal move of its kind in world rugby and, if successful, could force change to the way the game is played.

Lawyers for the group suggest another 80 former players between the ages of 25 and 55 are showing symptoms and have serious concerns.

World Rugby told the BBC: "While not commenting on speculation, World Rugby takes player safety very seriously and implements injury-prevention strategies based on the latest available knowledge, research and evidence."

The RFU said it had not had any formal or informal approaches, with any legal documents being served, while the Welsh Rugby Union has yet to respond.

Thompson retired in 2011 due to a neck injury after collecting 73 caps for England and spending his club career at Northampton Saints and Brive.

The hooker credits the sport going fully-professional as part of the reason he has sustained head injuries.

“When we first started going full-time in the mid-1990s, training sessions could quickly turn into full contact. There was one session when the scrummaging hadn't gone quite right and they made us do a hundred live scrums,” he said.

“When it comes to it, we were like a bit of meat, really.”

Richard Boardman, the lawyer representing the players in the multi-million pound suit, has revealed while eight players are in the first group suing, he is already talking to 100 former players.

He said: "We are now in a position where we believe the governing bodies across the rugby world are liable for failing to adequately protect their players on this particular issue.

"Depending on how many people come forward, the case could be worth tens of millions, maybe even hundreds of millions. Right now we're representing over 100 former players but we expect many more to get in contact."

Several high profile deaths in the world of football have also shone a light on the link between sport and braindamage.

The links between heading a football and degenerative brain disease have even forced rule changes at youth level.

In England, Scotland and Northern Ireland, children aged 11 and under are no longer allowed to head the ball in training, with limits on heading frequency at higher age group levels.

Former professionals have called for more research and better player welfare after the recent death of England World Cup winner Nobby Stiles, and the news that Stiles' 1966 team-mate and Manchester United legend Sir Bobby Charlton is suffering from the disease.