Miss Irby is alleged to have kissed a man, allowed him to him to fondle her breasts and stripped down to her underwear during the long haul flight from India to the UK.
She is also accused of leaving her two-year-old son to run around the Indian Kingfisher Airlines aircraft and throwing a soiled nappy onto a seat.
Fellow passenger Polly O’Callaghan, seated two rows behind her, told Isleworth Crown Court that she noticed Miss Irby’s erratic behaviour about two hours after take-off from Bangalore.
She said the 30 year-old blonde from Fulham, west London, spoke loudly to gain attention and was rude to the staff on board the flight last March.
Miss O’Callaghan described how she saw the defendant talking to a man in the row behind her, 36-year-old Daniel Melia, and drinking several glasses of red wine with him.
“The gentleman and the female became quite flirtatious and he was touching her face over the seats. She said she ‘I am not normally this relaxed, it’s just all the opium I have been taking’. I distinctly remember hearing that.”
Under cross examination, the speech and language therapist added: “She may have said it in jest, but she said it.”
Miss O’Callaghan, from Chiswick, west London, said Miss Irby – who denies being drunk on an aircraft - used the call button in her seat every 10 minutes over a two hour period to summon the air stewards to her seat.
At one stage she called one crew member a “bitch” and tossed aside a soiled nappy, the court heard.
“I saw her throw a dirty nappy on the seat, she threw it on the seat behind her,” said Miss O’Callaghan. “I think she did it because she thought the air hostess hadn’t come quick enough.
“She asked for a nappy bag, she asked for a wet wipe. She also said ‘get this ---- off my hands’.
Miss O’Callaghan said she complained to the stewardesses on board the 10 and a half hour flight because she was concerned that Miss Irby’s son was not being looked after.
“I was concerned about the welfare of the child when she was asleep on the aeroplane. I was so concerned because she wasn’t paying any attention to the child.”
She said Miss Irby complained about the way she was treated when refused alcohol and being told to behave: “She said she didn’t think she would be treated like this on British Airways. She said it in a very abrupt manner.”
Earlier, the court heard how Irby was described as “on the verge of being dangerous” by the aircraft’s captain, Vivek Sondhi.
Mr Sondhi said he notice a man and a woman “sprawled” over two rows of seats when he walked around the aircraft four hours into the flight.
He said they invited him to join them for a drink: “When I was in economy, I saw these two people. They asked me for a drink which of course I refused.
“It normal circumstances, there is no guest on board who will offer a captain a drink. It is very abnormal.”
On arrival back to the UK on March 26 this year, the aircraft was met by the Metropolitan Police and Miss Irby was arrested.
PC Mark Dady said he thought she appeared drunk as he escorted her off the plane.
“She was unsteady on her feet, her eyes were glazed and she smelled strongly of intoxicating liquor,” he said. “I would say she was drunk.”
But the court heard that she was not deemed to be intoxicated by the doctor who examined her and Mr Dady conceded: “I could have been mistaken, but from what I saw at the time, in my opinion she was drunk.”
Miss Irby, whose late grandfather Robert Henderson was the chairman of Kleinwort Benson, the private bank, insisted she had no more than four or five glasses of win during the flight and was very tired.
She told police the alcohol had affected her more than normal because she had not eaten properly but denied exposing her underwear or throwing a dirty nappy.
Mr Melia was also arrested on arrival but is not before the court, while his girlfriend Sarah Hannon, who was travelling with him, was also arrested but no further action taken.
The trial continues.
By Caroline Gammell
September 15, 2009