LONDON • Officials from the United States Anti-Doping Agency (Usada) will speak to senior figures in British Athletics this week after they had questioned athlete Mo Farah for five hours about his coach Alberto Salazar on Saturday.

Among those expected to be interviewed are British Athletics performance director Neil Black and head of endurance Barry Fudge.

Both of them have worked closely with Salazar since Farah joined the Nike Oregon Project in the autumn of 2010.

Salazar was accused of a series of doping violations by a BBC Panorama documentary last month.

But he issued a 12,000-word riposte denying all charges.

In an arranged meeting at London's Grange Tower Bridge hotel, Farah told Usada investigator Bill Bock, who helped bring down cyclist Lance Armstrong, that he had never taken performance-enhancing drugs.

The British runner, who was flanked by his lawyers, also told Bock that he would split from Salazar if it was shown that his coach was involved in doping.

A source close to Farah told The Guardian: "Mo has got nothing to hide and he has always been happy to talk to Usada. The meeting was arranged several weeks ago."

Another source close to the investigation said double London 2012 gold medallist Farah was "just one of many in British Athletics who would be talking to Usada over the coming days".

Last month, Black told reporters that he went to Portland to see Farah and Salazar "at least six times a year" and said he also spent time with Salazar at training camps.

Black noted that Fudge "has probably spent a year out of the last four years of his life living and working directly with Mo on a daily basis".

Earlier this year, Black praised Salazar as a "genius" and "one of the best people to work with that I have ever come across".

He said that in the four years British Athletics had worked with Salazar, they had not had a falling out.

"There are more than 10 different people, not just in the same country but across the Atlantic, involved," he said. "An eight-hour time difference, five different training bases, constant variable travel and so on.

"But nobody has ever had a crossed word.

"The reason why is to do with this: Total trust, total belief, total respect. Alberto is so respectful of everyone else in the team, so knowledgeable of their contributions to the ultimate performance of the athlete that it becomes seamless.

"We have never had a challenge in all of the years we have been working together."

British Athletics has refused to comment directly on the news Usada will be speaking to its staff. But a spokesman said its independent review into its relationship with Salazar would be reporting its findings and recommendations early next month. THE GUARDIAN