Keep off drugs or athletics will die!

Jamaica’s Usain Bolt during a press conference in London. [AFP]

Usain Bolt has issued a chilling warning that "athletics will die" if a solution cannot be found to the drug problem plaguing the sport.

The sprint legend is set to bow out of track and field after the World Championships, which begin in London tomorrow.

But in the wake of frequent scandals, most notably the ongoing suspension of Russian athletes since 2015, he admitted to being worried about what he was leaving behind.

"Hopefully, athletes will see what’s going on and understand that if they don’t stop what they’re doing, the sport will die," Bolt said.

"Hopefully understand what the sport is going through and what they need to do as athletes to help the sport move forward.

"Personally I think it was there (rock bottom). After the scandal on Russia I don’t think it gets any worse than that. It’s on its way back up now. No way but up you can go and forward.

"You can’t be happy about doping at all, it’s not good for the sport. But over the years we’re doing a better job, it’s getting clean and we’re catching a lot of athletes.

"I said a couple of years ago it had to get really bad, when there’s nowhere else to go but up. The only way track and field can go is up. We’re going to go in the right direction and I’m happy about that situation."

Bolt was speaking in London ahead of tomorrow’s 100m heats and Saturday’s semi-final and final as he aims to defend his world title from Beijing.

He will also race in the 4x100m relay next week before bringing the curtain down on his decorated and stunning career.

Yet his preparations were hit when close pal and British high jumper Germaine Mason was killed in a motorbike accident in April following a night out with Bolt in Jamaica, and Bolt wants to bow out winning for his friend.

"For me it was a rough time. I have never had someone who passed away so close to me. It set me back a little bit and I didn’t train for three weeks maybe," said Bolt.

"And my coach gave me my space, he gave me time to get over it. But at some point just the close net of people I was with said, ‘Listen to us Usain, I know it is hard but you need to get back training... Germaine would have wanted it.'"

Bolt insists he is ready for London - where he first defended his Olympic titles in 2012 - and wants his legacy to stand the test of time.

"Unbeatable. Usain Bolt has retired unbeatable over that event."