LONDON (Reuters) - Britain's anti-doping agency has opened an investigation into newspaper allegations that doctors in Kenya supplied prohibited performance enhancing drugs to British athletes.

Undercover footage taken by the Sunday Times showed two Kenyan doctors and an associate claiming that they had given British athletes EPO, a banned blood-boosting drug.

"UK Anti-Doping has reviewed the evidence presented to us by The Sunday Times and it is of grave concern and of significant interest," UKAD chief executive Nicole Sapstead said in a statement.

"We have opened an investigation and are taking the necessary steps to corroborate the evidence and investigate it further."

The investigation by the Sunday Times, conducted with German broadcaster ARD/WRD, said three men had been arrested by Kenyan authorities last week, having reviewed the film footage.

The newspaper said the two doctors claimed to have given a British athlete a series of EPO injections in preparation for a major race. An associate of the doctors said three other Britons were among about 50 athletes he had supplied with prohibited substances.

Some British athletes use Kenya as a base for training, with its high altitude and warm weather providing better conditions for them to prepare in.

However, UKAD's Sapstead warned that some countries where British athletes train might not have "the necessary anti-doping systems in place", and encouraged every sport to identify any risks related to the location of training regimes.


The Sunday Times also said it had photographs of empty EPO packets that had been discarded at the High Altitude Training center in Iten, western Kenya, while British athletes were staying there.

However, the owners of the center said that doping was not tolerated.

"We have installed 16 cameras to monitor the camp. If we have any concerns about athletes, we immediately report the athlete to the IAAF who will normally test the athlete that same day," Pieter Langerhorst, who owns the center with his wife, told The Observer.

The International Association of Athletics Federations, or IAAF, is the sport's global ruling body.

UK Athletics, which govern's the sport in Britain, described the allegations as "vague and unsubstantiated" and said it needed "much more detail to be able to respond fully".

It added in a statement: "To be clear, none of the allegations as presented relating to British athletes accords with our experience.

"Nevertheless, we take any allegations of doping seriously and will as always cooperate fully with any investigation undertaken by UKAD or other anti-doping organizations."

The World Anti-Doping Agency said it would review the evidence that UKAD compiles and take any action necessary.

“WADA is grateful to The Sunday Times and ARD for bringing the evidence to UKAD’s attention,” WADA director general Olivier Niggli said in a statement.

"...this is an indication that the Kenyan government must quickly put the necessary human resources behind Anti-Doping Agency of Kenya in the interest of protecting clean sport."

(Reporting by Alistair Smout; Editing by Ken Ferris)