Welsh rugby chiefs are set to investigate serious drug abuse allegations made yesterday by former Wales and Lions great JPR Williams.

Williams, fullback-star of Wales' all-conquering 1970's team, is among a clutch of internationals, including England's Jonathan Webb and Jeff Probyn, who have voiced concerns about drugs and their sport.

"Taking banned substances is fairly rife, and most of it is done in the off-season," Williams said.

"It is fairly well recognised that certain players have been on anabolic steroids and haven't been tested.

"I know of two players in Wales who are still playing, and have played at international level. I have had it confirmed by the two players," he told the Sunday Times.

Williams, capped 55 times by his country and standing fourth on Wales' all time appearance chart, is likely to spark a thorough Welsh Rugby Union probe.

"JPR's accusations are obviously serious ones, and it does seem strange that he has not voiced his concern directly to the Union," said a WRU spokesman.

"The innuendo leaves an unsatisfactory feel about it, and it is now down to the Union to follow through what has been alleged and to ascertain what substance there is to JPR's concern."

Williams' fears were confirmed, meanwhile, by former England and British Lions prop Mike Burton, who said: "Drugs are a problem. It is obvious from some of the body shapes you see that they are not natural."

No English based players have yet tested positive for drug abuse, but positive tests were carried out on former Wales B and South Wales Police centre Richie Griffiths and ex-Llanelli forward Paul Jones.