Mo Farah watched in near-silence as his wife launched a foul-mouthed tirade against an airline worker because the family were told to wait alongside economy passengers, a shocked eyewitness has revealed.
The Olympic hero's partner Tania was said to have been furious when the couple and their daughter Rihanna were told they had missed first-class boarding as they made their way back from Rio.
Asked to wait until all passengers from the gate had boarded before they could make their way on to the plane, Mrs Farah, 30, began swearing at the attendant, it is alleged.
Waiting flyers heard the wife of the four-time gold medal winner call the woman, 'f****** pathetic', tell her she led a 'sad little life' and say she was being 'disrespectful' to the family, it is said.
According to the witness, the outburst - in the presence of Farah's 11-year-old stepdaughter and other young passengers - went on for up to ten minutes as the Delta Air Lines worker failed in her attempts in calming Mrs Farah down.
The witness said this only prompted her to add: 'I demand an apology for the way we have been treated.'
The alleged incident took place just two days after Farah won his second Rio gold in the 5,000m. His family were boarding a 9.53am flight from Atlanta, Georgia, to their home in Portland, Oregon, in the US on August 22.
The 33-year-old was still sporting a Team GB holdall and Rihanna was hugging a Pride the lion Team GB cuddly mascot. Witness Jen Erdmann, a US government worker, said the commotion began as soon as the Farahs attempted to board.
With no separate queue for first-class passengers, the group were told to wait until the flight had boarded, it is said
Mrs Erdmann said: 'The agent told her to stand to the side and wait. When she was right next to the gate agent she started laying into her. I didn't even recognise Mo but was listening because of this argument.
'It wasn't at the top of her voice but loud. Mo stood there with their daughter but if that were my kids they would be so embarrassed. She called the agent disrespectful a lot of times.
'When a supervisor arrived Tania referred to the agent as "this pathetic little woman",' said Mrs Erdmann, from Atlanta. 'She said she was taking her sad little life out on them.
She was swearing a lot, it was peppered throughout. She talked about "f****** problems on this f****** airline".
'She kept saying the woman was being disrespectful and I thought she meant it in terms of being a celebrity.'