The IAAF president, Sebastian Coe, is facing a fresh crisis after an email was leaked showing that his right-hand man knew about a number of Russian doping cases in 2013, and discussed a secret plan to delay naming those involved before the World Championships in Moscow that year.

In the email published by the French newspaper Le Monde, Coe’s close confidant Nick Davies – the International Association of Athletics Federations’ deputy general secretary – also suggested that athletics’ governing body might use Coe’s political influence and his sports marketing firm Chime Sports Media (CSM), as an “unofficial PR campaign” to “stop attacks planned by the British press towards Russia”. As Davies explained in a “very secret” email to former IAAF marketing executive Papa Massata Diack, son of the former president Lamine Diack, he planned to “sit down to talk with the Anti-Doping Department and understand exactly who are the ‘corpses’ Russians that are still in the cupboard, in relation to doping”.

In the email, which was sent on 19 July, 2013 – just 22 days before the start of the World Championships in Moscow – Davies admits that the IAAF should have unveiled the “various [Russian] athletes a long time ago” but says “now we need to be smart”.

After stressing that the athletes who cheated should not be part of any Russian team for the World Championships “and Valentin [Balakhnichev, the IAAF treasurer and head of Russian Athletics] should be pressurised to make sure this is the case”, Davies outlines a plan to minimise the damage. “If the guilty ones are not competing then we might as well wait until the event is over to announce them,” he writes. “Or we announce one or two but at the same time as athletes from other countries. Also we can prepare a special dossier on IAAF testing which will show that one of the reasons why these Russian athletes come up positive is that they get tested a lot!!!”

At the time of the email, Russia’s suitability to host the World Championships in 2013 was being questioned after a series of doping allegations. In the four months after the event the IAAF announced sanctions against 16 Russian athletes.

In his email to Papa Diack, Davies also suggested that the IAAF might take advantage of Coe’s influence with the UK media by using his CSM agency as part of a PR strategy. “I believe if we consider using CSM we can also benefit from Seb’s political influence in the UK,” wrote Davies. “It is in his personal interest to ensure that the World Championships in Moscow are a success and that people do not think that the press in his country wants to destroy them. We will work hard to stop all attacks planned by the British press towards Russia in the coming weeks.”

The email is bound to cause Coe huge embarrassment given that one of his first acts after becoming IAAF president in August was to promote Davies from press spokesman to run his office. It may also make those sceptical of his promises to change the sport further question his judgment. Davies concludes his email to Papa Diack by telling him that he will do “everything in my power to protect the IAAF and the president”. Given the reputation of athletics’ governing body, that looks ill-judged in hindsight.

In recent months Papa Diack has become one of a number of former IAAF figures to face charges of extorting money from the Russian marathon runner Liliya Shobukhova to hide her doping. While only last week Le Monde also reported that Diack Snr, who is being investigated by French police for corruption, had confessed to asking for €1.5m from Araf and that the IAAF had intentionally slowed doping cases involving Russian athletes.

In a statement Davies denied any wrongdoing, and said he was merely exchanging ideas about possible strategies related to “serious challenges” faced around the image of the competition. “No plan was put in place following this email and there is absolutely no possibility that a strategy or a media plan/PR may interfere with the anti-doping procedure,” he added. “I have not discussed these ideas with CSM and there was never any agreement between the IAAF and CSM to develop a public relations campaign.”

But the leaking of his email to Le Monde will heap further pressure on the IAAF. Last month an Independent Commission report by the World Anti-Doping Agency revealed that there was systemic state-sponsored doping in Russia and warned of a “conspiracy to conduct and conceal corrupt behaviour by particular highly placed members and officials of the IAAF and the Araf [the Russian Athletics Federation]”.

Several other former senior figures at the IAAF, including Papa Diack, Balakhnichev, former IAAF anti-doping chief Gabriel Dollé and Lamine Diack’s special legal adviser Habib Cissé are also being investigated by French police for allegedly taking bribes to cover up positive tests.

Papa Diack, Dollé and Balakhnichev are also awaiting the decision of the IAAF’s ethics committee on charges of extorting money from Shobukhova. They deny the charges but face life bans if found guilty.

Coe’s spokeswoman Jackie Brock-Doyle said her client would not be responding to the story. “What is very clear is that Sebastian will not respond to emails to which he knows nothing,” she said.