Scotland Yard chief Sir Bernard Hogan-Howe is to meet the widow of former home secretary Lord Brittan to explain his force's handling of a historical rape allegation against her husband.
The Metropolitan Police commissioner is expected to apologise to Lady Brittan at the meeting at a central London hotel after her husband died in January last year without being told he would not face any action over the claim.
Britain's largest police force has come under fire over its handling of the claim that Lord Brittan raped a 19-year-old woman known as "Jane" in 1967.
The meeting between Lady Brittan and Sir Bernard comes amid intense scrutiny of the Met's Operation Midland, a separate inquiry into allegations of a VIP paedophile gang.
As well as historical abuse claims, the investigation is also examining allegations that three young boys were murdered.
But there have been suggestions that the inquiry, which had cost £1.8 million as of November, is on the brink of collapse amid questions about the reliability of the central witness in the investigation, a man known as "Nick".
A furore erupted over Operation Midland after D-Day veteran Lord Bramall was cleared of historical abuse allegations.
His home had been raided and he was interviewed under caution before he was told in January he would face no further action.
Former Tory MP Harvey Proctor, who furiously denied any involvement, has been interviewed under caution twice but there are unconfirmed reports that he will also be formally told he will face no further action.
The late former prime minister Edward Heath has also been named in connection with the inquiry.
When the investigation was launched, a detective described Nick's account as "credible and true".
The force later acknowledged the description had "suggested we were pre-empting the outcome of the investigation".