Retired England and Wales rugby union internationals are among six former players suffering from concussion-related health problems to have joined a lawsuit against the game.

A pre-action letter of claim was on Thursday morning delivered to World Rugby, the Rugby Football Union and Welsh Rugby Union on behalf of nine players being represented by Rylands Law.

In addition to England forwards Steve Thompson and Michael Lipman and Wales flanker Alix Popham, 30-year-old Wales Under-20 centre Adam Hughes and 44-year-old England Under-21 back row Neil Spence have also chosen to sue.

Four of the six new claimants have asked to remain anonymous, but the PA news agency understands they include one former England and one former Wales international.

Thompson revealed last week that he has no recollection of taking part in the 2003 World Cup triumph in Australia because of the brain injuries sustained during his career.

The basis of the claim made on behalf of the nine test cases – Rylands Law say they are talking to over 130 more retired players – is that the sport’s governing bodies failed to provide sufficient protection from the risks caused by concussion.

Hughes has been diagnosed with having brain injuries and post-concussion symptoms since his career was ended in 2018, while the remaining eight have been diagnosed with traumatic brain injury, early onset dementia and probable chronic traumatic encephalopathy (CTE).

CTE is a progressive degenerative disease of the brain found in people with a history of repetitive brain trauma and was previously known as punch drunk syndrome and dementia pugilistica.

Rylands Law alleges that the risks of concussions and sub-concussive injuries were “known and foreseeable” and lists 24 failures on the part of World Rugby, RFU and WRU.

The governing bodies have a maximum of three months from the date of acknowledgement of the letter of claim to provide their initial response. The letter focuses on “broad allegations” rather than “an exhaustive list of the evidence”.

In reply, the governing bodies issued a joint statement outlining their position.

It read: “World Rugby, the RFU and WRU can confirm they have received a letter of claim from solicitors representing certain players and will now take time to consider its contents.

“We have been deeply saddened to hear the brave personal accounts from former players.

“Rugby is a contact sport and while there is an element of risk to playing any sport, rugby takes player welfare extremely seriously and it continues to be our number one priority.

“We will continue to use medical evidence and research to keep evolving our approach.

“As with any potential legal proceedings, it would be inappropriate to comment on the specifics of the letter.”

Richard Boardman of Rylands Law insists some of the test cases will demonstrate the potential harm caused by playing the sport no matter the position.

“Last week’s announcement about the condition of some of rugby’s sporting greats has sent shockwaves around the sport. Yet, for many, it was inevitable,” Boardman said.

“I think what will surprise people when they see the test cases is the age of the players, but also the positions in which they played.

“You don’t have to be a bruising forward in the middle of the scrum to suffer concussive injuries.”

England’s former team doctor has admitted to missing concussions and wants action to protect players.

Dr Phil Batty, who was senior team doctor from 2012-2014, told ITV News: “I have missed concussions where I’ve taken people off for assessment and they’ve been assessed independently or by myself and they’ve been allowed back on the field of play.

“But with hindsight they were clearly concussed, and it became apparent that they were concussed.

“I really hope rugby learns, listens more, and I do think there are going to have to be some significant rule changes to how the game is played.

“It’s become much more of a collision sport, it’s become much more about the collision, the gain line and I just think that needs to be thought through and revisited.

“I love the game of rugby and I really want it to thrive but it needs to change.”