Lord Brittan's widow should have been informed that he would not have faced action over a rape allegation sooner, Scotland Yard has admitted.
Investigating officers told the complainant in April that there would not have been a prosecution had the late peer been alive, but his legal team were not told at the same time.
The Metropolitan Police today published the key findings from a report ordered after the force apologised to Lady Brittan. It followed a furore over allegations raised by Labour deputy leader Tom Watson.
In a lengthy statement the force also disclosed that commissioner Sir Bernard Hogan-Howe has asked a separate force to review the investigation to ensure it was thorough and properly conducted.
Lord Brittan died in January without being told he had been cleared of a rape allegation.
The Met Police said the full report into its handling of the affair was confidential but published a summary of its details which named Lord Brittan for the first time "because of the unique circumstances of the case".
It concluded: "The MPS accepts that Lord Brittan's solicitors should have been informed at the same time as the complainant was informed.
"This would have permitted them to clarify the position with Lady Brittan, for which the MPS apologised in a letter to her solicitors on 6 October 2015.
"There had been no previous contact between the MPS and Lady Brittan during the investigation as it is not normal procedure to inform anyone other than the person accused of the offence.
"Relatives of people who die whilst under investigation would not normally be contacted after their death and would not be told what the outcome of the investigation would have been, or indeed whether it would have led to a charge or not.
"But the MPS recognises - as it did throughout the dialogue with the CPS - that the public interest in the case required a different approach."