Nigella Lawson will not be prosecuted for taking cocaine, despite admitting it during the recent fraud trial of her two assistants.
The Metropolitan Police said a specialist team had examined all the evidence relating to the 54-year-old TV chef's confessions but has concluded there will be no further action.
Nigella revealed during the trial of sisters Elisabetta and Francesca Grillo, that she took the Class A drug with her late husband John Diamond when he found out he had terminal cancer.
She also admitted taking it in July 2010 when she claimed she was being 'subjected to intimate terrorism' by her former husband, Charles Saatchi.
During the trial at Isleworth Crown Court, Mr Saatchi testified: "I have never, never seen any evidence of Nigella taking any drugs whatsoever. I want to be helpful, but I genuinely have no real knowledge at all."
In response to one question, he said: "Are you asking me whether I think Nigella truly was off her head? Not for a second. Over this whole period she was writing books very successfully and appearing on television shows very successfully."
Police revealed that they took the decision that prosecuting Nigella – who is currently on TV as a judge on Channel 4's Taste - was not proportionate and might put witnesses off telling the truth in trials.
A Scotland Yard spokesman said: "A specialist team from the Metropolitan Police Service has now examined all the available evidence in relation to admissions of drug use made during the trial of Elisabetta and Francesca Grillo at Isleworth Crown Court.
"The review has concluded that there will be no further action by police. "The decision has been taken based on a number of factors, including the need for police action to be proportionate, whether further action would be in the public interest, and after consultation with the Crown Prosecution Service.
"There are serious public interest concerns about the message any prosecution would send out to potential witnesses and victims in the future.
"Whilst witnesses clearly cannot simply admit to any offence under oath without consequences, this has to be balanced with the requirement for victims and witnesses to tell the truth.
"Further police activity may deter victims from being candid with police and in court for fear of future investigation."