World Cup winner Steve Thompson has packed away all his medals, trophies and memorabilia. Since he began to lose his memory, having reminders around is just too painful.

"I feel like a phoney," says the 44-year-old. "It feels like I haven't done it."

What's more, Thompson actually wishes he hadn't done it. Because then perhaps he wouldn't now have early onset dementia he believes was caused by taking hundreds of blows to the head during his career.

"If I hadn't done it, I might not be such a burden on the family," he says.

This all plays out during a harrowing hour-long BBC Two film which follows Thompson.

In another scene, he tries to describe the "out-of-body" sensation of the brain fogs he suffers, when he suddenly drops out mid-sentence. It's incredibly illustrative.

We also see upsetting moments where he forgets the names of his children, or describes leaving his car running for hours.

It is clear dementia has had a hugely detrimental impact on Thompson's life; he has spoken previously about how he has had suicidal thoughts.

In 2020 he was one of a group of players who launched a legal case to sue rugby's governing bodies for negligence.

The film documents all of this - from Thompson and his family trying to come to terms with his diagnosis, to him lending his voice to the fight to make rugby safer.

The release of the documentary comes after new research was published from a study examining a link between sport and neurodegenerative diseases such as Parkinson's, motor neurone disease (MND) and dementia.

The study's lead, consultant neuropathologist Professor Willie Stewart, called for rugby authorities to consider eliminating contact training and reduce rather than expand the global calendar.

'You were just told to get on with it'

Thompson was diagnosed in 2020 with early onset dementia, which he says is most likely to have been caused by a brain condition called chronic traumatic encephalopathy (CTE).

As he says in the film "this degenerative disease is caused by multiple head impacts, known as sub-concussions".

During the film, Thompson visits Prof Steve Gentleman - a professor of neuropathology at Imperial College London. Prof Gentleman explains that CTE is a condition that worsens with time, and for which there is no known cure.

Thompson is convinced the source is the multiple head impacts he suffered as a player.

He was part of the generation that were playing when rugby turned professional in 1995 and tells BBC Sport he believes protocols at the time around concussion and full-contact training were not safe. He describes doing 100 live scrums in a single training session.

"If you were knocked out and you came back to, you were just told to get on with it," he says.

"If you had a headache, you were just given headache pills. It wasn't known as an injury. It would be like: 'At least you haven't pulled your hamstring, so you can still run.'"

Thompson says players were told their heads were their "biggest weapon" in some contact situations.

As a hooker, he was front and centre of the 16-man scrum, and says the pressure on his head would be "enormous".

"We had a scrummage session where the scrum machine was pegged it into the ground, so it wouldn't move," he says.

"Rather than the machine moving a little bit, the pressure's coming all through your body. Then they break off to go into some rucks, and the pressure just goes all into your head.

"As you come off, you pass out. They'd give me a few seconds to come around and then do it again. You'd have burst blood vessels all around your eyes where you've been pushing so hard."

'You don't feel like you deserve to be on this earth'

Thompson describes how he is now prone to mood swings, depression and forgetfulness.

During the film, there are times when he can't remember his children's names.

"We've got young kids," says his wife Steph. "It's sad thinking you might not know them when they're teenagers."

Thompson tells BBC Sport he now needs much more rest time, describing his brain as like "a really old Nokia phone" that must have "12 hours charging in order to get an hour's activity".

He also says he has lost jobs because of his condition.

"When I came out and told people, how many people wanted to employ me? To them, I'm broken," he says.

"If you've been diagnosed with dementia and you're on a work site where someone else gets injured, the insurance companies won't pay out.

"It's not until you're there yourself that you understand. You don't feel like you deserve to be on this earth, and you don't feel like you deserve to drag everyone else down."

Thompson also shares some of the techniques his therapist has taught him to cope with tougher moments.

"I spray perfume of Steph's on my arm and stuff," he says. "Certain pictures on my phone - when I start getting anxious, they pull me back out of it."

'There's not many care homes that will take young men'

Thompson is among more than 185 players suing rugby union's governing bodies for negligence, claiming that playing the sport caused brain damage.

During the film, he describes some of the negative responses that action elicited, including being trolled by rugby fans.

He is also disappointed by the response from rugby authorities - including the Rugby Football Union (RFU), which is the game's governing body in England.

"There's been no support from the RFU," he says, "Since I started the legal action, they've even stopped sending me the birthday card I got every year."

Thompson argues he needs compensation in case he needs specialist care.

"I don't want my kids to have to give up their lives to look after me," he says.

"If I have to go into a home, you're talking £10,000. And there's not many care homes that will take young men.

"I did my job. I trained as hard as I possibly could. It's other people's jobs to look after you."

Concussion protocol 'a little start'

As well as seeking compensation, Thompson wants rugby to be made safer, including less contact training, a longer stand-down period for players returning from concussion, and a process of brain scans.

He asks: "In France, they have heart scans and, if players' hearts aren't quite right, they're not allowed to play. What's different with a brain?"

In July 2021, an MPs' inquiry concluded sport had been allowed to "mark its own homework" on reducing the risks of brain injury, recommending a standard definition of concussion that all sports must use, and a paid medical officer at every major sporting event.

In September last year, World Rugby recommended limiting full contact training to 15 minutes per week.

Thompson contrasts that to his playing career, when he says he would be doing about 10 hours of contact training per week.

But he believes it is not enough for recommendations to be made.

"I'm glad they've finally done something, it feels like a bit of a joke," he says in the film, adding: "As it's not a statutory ruling and only advisory - it can easily be ignored."

In June this year, World Rugby extended its concussion stand-down period from six to 12 days.

Again, Thompson feels the sport could go further.

"It's a little start, but, to be honest, it needs to be three weeks at least," he says, adding he would still not feel comfortable allowing his children to play full-contact rugby.

In a statement, World Rugby said: "We embrace innovation and technological advancements to further the identification, management and prevention of head impacts in rugby.

"This proactive commitment has delivered advancements in the laws of the game, revised guidance on contact training load, groundbreaking research using instrumented mouthguards and, in the case of former players, access to brain health consultation and brain health education."

The RFU, meanwhile, said it had "played an instrumental role in establishing concussion and injury surveillance, concussion assessment, and supporting law changes to ensure proactive management of player welfare".

It added: "We and the Rugby Players' Association have made contact with all former players to share the work we have and our doing to help players, including the launch last year of an advanced brain health clinic for retired players."

Northampton Saints, where Thompson spent the bulk of his professional career, said: "Player welfare is always a priority. Concussion protocols have been implemented and followed in a timely manner… to ensure appropriate monitoring for and management of head injuries."

If you, or someone you know, have been affected by any issues raised in this article, support and information is available at BBC Action Line.