Art mogul Charles Saatchi took the stand in a London courtroom Friday and refused to admit that ex-wife celebrity chef Nigella Lawson has a cocaine habit — despite sending her seething e-mails attacking her “depravity” because she’s “so off her head on drugs.”

The former advertising czar — who infamously grabbed his ex’s throat during an argument at a London restaurant in July — testified, “I have never, never seen any evidence of Nigella taking any drug whatsoever. I want to be helpful, but genuinely I have no real knowledge at all.”

He instead insisted he’s crushed by their split and still loves the buxom ­domestic diva.

“I adore Nigella, and I’m absolutely brokenhearted to have lost her,” Saatchi, 70, said at a London courthouse where two of his former assistants, who are sisters, are facing fraud raps for running up $1.1 million on his credit cards.

Charles SaatchiFilmMagic

Saatchi testified that Lawson was way too busy with work to be strung out.

“Over this whole period, she was writing books very successfully and appearing on television shows very successfully,” he said.

Saatchi also explained that the infamous restaurant throttling was simply a misunderstanding.

“I was not gripping, strangling or throttling her,” Saatchi explained. “I was holding her head by the neck to make her focus, can we be clear? Was it about her drug use? No,” he said, without elaborating.

But in October, Saatchi sent Lawson, 53, seething e-mails, which were read aloud in court this week.

“Nigella . . . I can only laugh at your sorry depravity,” Saatchi wrote. “You . . . were so off your head on drugs that you allowed the sisters to spend whatever they liked.

“But I’m sure it was all great fun and now everything is perfect — bravo, you have become a celebrity hostess on a global TV game show. And you got the pass you desired, free to heartily enjoy all the drugs you want, forever. Classy,” he wrote.

The art mogul said he has been devastated by their public release. “I’m utterly bereft that this private e-mail to Nigella has come back to haunt us both.”

Their former assistants, Francesca, 35, and Elisabetta Grillo, 41, are accused of ringing up more than $1 million on Saatchi’s credit cards during shopping sprees.

The siblings have countered that they had a “tacit” understanding they could spend as they pleased as long as they kept the lid on Lawson’s alleged marijuana, cocaine and prescription-pill consumption.

The Grillos embarked on epic shopping trips in which they splurged on everything from Prada and Louis Vuitton to stays at the Gansevoort Hotel in Manhattan.

Saatchi testified that Lawson was infuriated that he suggested they reason with the sisters after their spending habits came to light — and she instead wanted to call the cops.

The sensational trial is slated to continue next week and Lawson is expected to testify.