LONDON, England (AFP) — Anti-doping chiefs unveiled a new weapon in the fight against drug cheats yesterday as they vowed to stage the most rigorously tested Olympics in history.

World Anti-Doping Agency (WADA) director general David Howman confirmed that for the first time a sophisticated test for human growth hormone (HGH) approved earlier this year would be used at the London Games.

The “bio-marker” test, which had been in development for more than a decade before being approved, was capable of distinguishing between HGH produced naturally in the body and synthetic HGH, Howman told AFP.

“It’s a very significant step and it’s a very helpful one,” Howman said following a WADA briefing. “Every step is significant if it ends up catching someone who has been cheating with impunity.

“Essentially it differentiates between the human growth hormone that is produced in the body naturally and that which has been introduced by artificial means.”

Crucially, the new test had a detection window of “weeks rather than hours,” Howman said.

Meanwhile WADA president John Fahey said an extensive pre-Olympic testing programme meant London would be the most “tested Games” in history.

“We’re helping to provide an Olympic games that is as free from doping as is possible,” Fahey said.

A mammoth 71,649 tests had been carried out worldwide in the six months leading up to July 19, with 107 athletes sanctioned. London organisers say more than 6,000 tests will be carried out during the games itself.

Fahey also reiterated that under WADA rules, samples would be retained for a period of up to eight years after the games meaning that drugs cheats would never be able to rest at ease.

“London 2012 will be the most tested games in Olympic history,” Fahey said. “I would also like to remind athletes and their entourages that samples can be stored and retested for up to eight years after the Games,” he said.

“If someone thinks they’re home free in 15 days time from some form of cheating, then they should hold their breath for eight years because the odds are they can be picked up at any point in that period,” Fahey added.

Six athletes had been suspended for offences using the IAAF’s “biological passport” system, while three others, including 2008 Olympic 1,500m bronze medallist Nataliya Tobias, had been caught as a result of re-testing of samples from the 2011 World Championships in South Korea.