Celebrity cook Nigella Lawson said she was "disappointed but unsurprised" after her two former personal assistants were cleared of fraud.

The TV cook added that her experience as a witness was "deeply disturbing" and that the jury was "faced with a ridiculous sideshow of false allegations" about drug use which made the actual criminal trial impossible.

Francesca Grillo, 35, and her sister, Elisabetta, 41, were found not guilty of one count each of defrauding Charles Saatchi and his ex-wife Ms Lawson.

Read: Nigella personally hurt but professionally unscarred

During the three-week trial the celebrity cook admitted she had taken cocaine in the past, after allegations of drug use arose as part of the defence case.

Scotland Yard said it would not be investigating claims Ms Lawson took cocaine unless new evidence comes to light.

When false claims about habitual drug use were introduced, I did everything possible to ensure the CPS (Crown Prosecution Service) was aware of the sustained background campaign deliberately designed to destroy my reputation.

Read: Full statement by Nigella Lawson after today's verdict

Ms Lawson claimed during the trial that multi-millionaire Mr Saatchi was threatening to "destroy" her and added that despite doing her civic duty, she was "maliciously vilified without the right to respond".

Nigella Lawson claimed her ex-husband threatened to "destroy" her. Credit: PA Wire

The Italian sister had been accused of spending hundreds of thousands of pounds on designer goods for themselves on company credit cards while working for the celebrity couple.

They said every purchase had been approved by their then-bosses.

The trial could have even collapsed after** Prime Minister David Cameron declared his support for "Team Nigella"** in a magazine interview halfway through the trial.

His comments prompted the defence calling for the trial to be brought to an end.

David Cameron's comments nearly brought an end to the trial. Credit: PA

Neither sister had been in court when the verdict was read out because the pair had been excused following Elisabetta suffering a panic attack yesterday.

Francesca's barrister, Karina Arden, was seen in the court foyer after the verdicts, proclaiming to her client: "C'e un Dio!" - Italian for "There is a God".

Francesca replied with a smile: "C'e un Dio!" and the pair embraced.