Ad Mogul Charles Saatchi -- 'Cautioned' By Cops After CHOKING WIFE

Advertising mogul Charles Saatchi -- one of the biggest art collectors in the world -- was given an official "caution" by London police after photos emerged showing the 70-year-old CHOKING HIS WIFE with his bare hands.

The story is exploding in the U.K. ... after photos surfaced showing Saatchi with his hands wrapped tightly around the neck of his wife Nigella Lawson -- a celebrity chef who recently appeared on "The Taste."

The photos were taken while Saatchi and Lawson were having dinner last week at Scott’s in Mayfair -- a very posh London restaurant.

Saatchi insisted he wasn't trying to hurt Lawson -- claiming they were merely in the middle of a "playful tiff." The look of sheer terror on Lawson's face says otherwise ...

Saatchi also said, "The pictures are horrific but give a far more drastic and violent impression of what took place. Nigella’s tears were because we both hate arguing, not because she had been hurt."

Lawson has reportedly left the couple's home with her children -- though Saatchi insists he sent her away to escape the media blitz until "the dust settled."