One of the tests occurred in early 2010 before he joined Salazar’s Nike Oregon Project.

The newspaper claims his second missed test occurred at his home in February 2011, when he claimed not to have heard the doorbell.

At the time, UK Anti-Doping (UKAD) rules stated that an athlete who missed three tests in any 18-month period could face up to a two-year ban.

That meant Farah could have been ruled out of his home Olympics with one more breach of the rules.

Nine UK athletes missed two tests in the same year.

The rules have since been amended and today athletes who miss three tests in a 12-month period can be banned for four years.

The Daily Mail claimed further correspondence showed Salazar had warned Farah on 5 May, 2011: "If you miss another test, they will hang you."

A source close to Farah has told the BBC that the athlete has not missed any tests since that second missed one.

The BBC programme levelled no accusations of any wrongdoing against Farah, who pulled out of the International Association of Athletics Federations’ Birmingham Diamond League meeting on June 7 and flew back to the United States.

Farah said he wanted  to “get answers” from Salazar, saying he was “emotionally and physically drained” and felt his name was being “dragged through the mud.”

Salazar and Farah’s training partner Galen Rupp, who is directly implicated by the allegations, have both strongly denied any wrongdoing.

Farah has subsequently announced he will run at the International Association of Athletics Federations Diamond League meeting in Monaco on July 17 but has yet to make any further statement about any discussions he may have had with his coach in the last couple of weeks.

The Athens 2004 heptathlon bronze medallist Kelly Sotherton has told BBC that missing a test “doesn’t mean you are doping.”

She said top-level athletes are tested up to 20 times a year and have to know three months in advance where they are going to be.

"This could be when you are on holiday - you still have to give your hotel details," she said. 

You are never free of drug testing.

"I've been tested nine times in six weeks before - at my house, at the track, at my partner's house.

"I can understand how a missed test could happen, and if you make a mistake once, most athletes learn from it.

"But a missed test doesn't mean you are doping.

“It may mean you have been a little bit careless - that doesn't make you a drugs cheat.

"I was very organised and I made a slip of a number by one day - that's how a missed test can happen."

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June 2015: Mo Farah's coach Alberto Salazar and training partner Rupp accused of doping