The 70-year-old art mogul drank almost a full bottle of red wine and smoked copiously during the lunch last Saturday. Trinny was also smoking but does not drink.
Saatchi showed apparent irritation as his girlfriend's distress escalated, gesticulating and glancing around to see if anyone was overhearing the conversation.
At one point she removed her glasses, glared at him and appeared to shout. After the plates were cleared away, Saatchi got up and asked for his drinks to be taken inside, and Trinny followed.
Soon afterwards, he returned to the table and she joined him minutes later, immediately demanding that he examine the elbow of her coat.
As the meal ended, Saatchi stalked off towards the taxi rank while Trinny sat alone at the table for a moment as if trying to compose herself. She then followed him to the waiting cab.
When contacted by The Mail on Sunday, Saatchi denied there had been an argument. He emailed: "Why not send a photographer to Scott's tomorrow lunchtime, and I will give Trinny a good throttling in time for your deadline?"
It is perhaps unfortunate that the images emerge as Saatchi admits for the first time that he is a 'narcissist' who cannot hold on to a woman.
In an astonishingly frank interview with Eton College's Junior Chronicle, a magazine to commemorate the school's traditional Fourth of June celebrations, he concedes that his self-obsession destroyed his three marriages to Doris Lockhart, Kay Hartenstein, and Nigella Lawson.
"If you are a narcissist as I am, you may find it difficult to hold on to your wives," he says, in his most candid confession so far. "I never quite comprehend how it is possible to tire of my company, but it clearly is, and with reliable frequency.
"Personally I find my own company perfectly exhilarating, but not when I'm alone."
But, perhaps most tellingly, he offers a hint that Trinny is not slated to be wife No 4, saying: "I always propose to a prospective wife on our second date. I feel that if they can handle a couple of suppers they will have a grasp of what to expect. But no, they always seem to give up the struggle, leaving me anxiously seeking another lifetime companion."
With unusual modesty, he says that his advertising success was "an almighty fluke".
He said: 'I am certain that I could never repeat this success and get rich again in any business.
"Advertising used to be an easy way for thick school drop-outs like me to earn eye-watering pay packets when we were young enough to spend it as madly as possible... By an almighty fluke (truly, I don't have a self-effacing bone in my body) I found I could translate my so-called skills as a copywriter into a money-making enterprise."
The sentiments about his relationships may or may not come as a surprise to Nigella, 54, who was pictured apparently being 'throttled' by Saatchi outside Scott's in June last year. He first dismissed the row as a 'playful tiff' but later accepted a police caution.
The couple's ten-year marriage unravelled after the publication of the pictures. She filed for a 'quickie' divorce and it was granted the following month. Saatchi responded by trying to plant stories in the national press that she was taking drugs with her children.
Then Nigella accused her ex-husband of waging 'intimate terrorism' against her.
Just eight weeks after their divorce was finalised, Saatchi started to date Trinny, best known for the TV show What Not To Wear.
She has told friends they are "hopelessly in love", but there have been claims she is increasingly frustrated by Saatchi's reluctance to both show affection in public and take their relationship to the next level.
When contacted by The Mail on Sunday, Saatchi was adamant that there had been no row between them and threatened legal action.
He said: "Please don't do this. There was no argument. This is so stupid."
In a fit of pique, he added: "Oh just run what you like. How would you like it if someone was looking at you [when you were eating]. It is a lie.
"Ask Trinny. This is beyond comprehension. I don't care what it looks like, you can ask me formally through my lawyer. How dare you. I give up."
The Mail on Sunday asked Trinny, and in reply received a response from lawyers acting for both her and Saatchi, denying there had been any falling-out.
While Saatchi makes headlines for the wrong reasons, Nigella is said to be 'thrilled' that her American TV show The Taste has been renewed for a third series after she finally secured her US work visa. It had been jeopardised after she admitted having taken cocaine and cannabis.
- Mail On Sunday