By Martha Kelner, sport correspondent
Professional rugby union players have lifted the lid on a culture of painkiller and prescription drug use in the game, particularly the powerful opioid tramadol.
The World Cup began on Friday, putting the sport in the spotlight for the next six weeks as the world's top teams compete for the Webb Ellis trophy.
But beneath the surface, concerns endure about the amount of legal drugs rugby players are taking and the potential long-term effects on their health.
In some countries, drugs are handed out freely, as if from a "cookie jar", according to one former international.
Ed Williamson, who played at Premiership and Championship level in England and later in France, has now retired and earns a living as an artist.
He says the demand on the bodies of top players means painkillers have become a necessary part of daily life for some professionals.
Now 35, he became addicted to tramadol after sustaining a particularly serious injury, even playing a game while high on the opioid.
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Williamson said: "I got back into the changing room before kick off and thought: 'The only way I'm going to get through this is if I pop a couple of these tramadols I have in my bag.'
"So I did and I was high the entire game.
"I remember the ball coming towards me. I had God knows how much time. I watched the ball bounce and went to catch it but it slipped through my hands.
"It was like everything was going in weird slow motion. I couldn't hear the crowd. It was just bizarre."
Tramadol is a strong painkiller which can become addictive. People who stop taking it suddenly can experience withdrawal symptoms including agitation, anxiety, shaking and sweating.
It is not currently on the World Anti-Doping Agency's banned list but it is on the monitoring list.
Some sports, including cycling's world governing body, the UCI, have already banned athletes from taking it.
Williamson said he believes there needs to be a tightening of controls around painkiller prescriptions given to players.
He said: "There needs to be some responsibility there, a little bit on the players' part but a lot on the medical side.
"There needs to be more monitoring of what players are taking."
Separately, a high-profile former England international told Sky News he inserted suppositories containing painkillers before every test match to mask the pain of collisions.
He said the queue for the toilet would extend round the dressing room.
Wales international Dominic Day, who currently plays for Saracens, worries about the amount of painkillers he was taking throughout his career. Together with teammate, England World Cup star George Kruis, he has launched a cannabis oil alternative, CBD oil.
He says doctors at Saracens act responsibly but describes a Wild West situation elsewhere.
"The place I've had the strangest situation in terms of handing drugs out would be Australia," Day sRead More – Source