French newspaper Le Monde yesterday published a series of emails from Davies, the IAAF's deputy secretary general, which included not naming Russian athletes who had failed drugs tests in the run-up the 2013 World Championships in Moscow. 

Davies also reportedly suggested hiring CSM, the sports marketing firm chaired by Coe, elected as IAAF President in August, to run a public relations campaign to deal with negative stories. 

The emails had been sent to IAAF marketing consultant Papa Massata Diack, son of former IAAF President Lamine Diack, who is now being investigated by the French authorities for accepting bribes to help cover-up positive drugs tests involving Russian athletes. 

Davies claimed in the emails they needed to "sit down" with anti-doping officials to discuss "Russian skeletons in the cupboard".

He added they "now need to be smart" about releasing names.

The Briton, a veteran IAAF official and longstanding communications director, who was promoted to Coe's chief of staff following his election in August, added that any Russian already caught doping should not be included in their country's team for the World Championships in the capital.

Davies' decision to step aside followed a long conversation earlier today with Coe, who he had already been told about the contents of the emails before they were published in the French media. 

Coe was not aware of them until that point and his firm CSM have never done any work for the IAAF. 

Davies claimed last night that none of the suggestions in his emails had been acted upon and he was just "brainstorming".

"In statements over recent days I have underlined that one of my key responsibilities is to manage and promote the reputation of the IAAF," said Davies.

"What has become apparent today is that I have become the story.

"This is not helpful at the current time, with ongoing criminal investigations by the French police, the IAAF’s Ethics Board or WADA (World Anti-Doping Agency) - all of whom I have voluntarily offered full assistance to and will continue to do so. 

"In order to demonstrate that I am willing to have all allegations of unethical behaviour on my part in 2013 properly and fairly investigated I have referred my emails to Papa Massata Diack in 2013, my statements and the circumstances of the emails to the IAAF Ethics Board.

"I have decided to step aside from my role with the IAAF until such time as the Ethics Board is able  to review the matter properly and decide if I am responsible for any breach of the IAAF Code of Ethics."

The IAAF's Ethics Commission is chaired by Michael Beloff,  a prominent English barrister.

Other prominent members include Australian Kevan Gosper, former vice-president of the International Olympic Committee, and Carlos Nuzman, the Brazilian who is President of Rio 2016 and the Brazilian Olympic Committee. 

Davies being dragged into the scandal is a blow for Coe, who had worked closely with him, particularly since the publication of the WADA Independent Commission report which found evidence of state-supported doping in Russia.

It led to the country's suspension from the IAAF, leaving in jeopardy their participation at next year's Olympics in Rio de Janeiro.

Further allegations about IAAF corruption are expected to emerge when the Independent Commission, chaired by Canada's Richard Pound, is due to publish the second part of its report in Munich on January 14.