Labour deputy leader Tom Watson will be questioned by MPs today over his role in the controversial police investigation in to the late Lord Brittan.
He will give evidence to the Commons Home Affairs Committee after being invited to appear in order to "clarify a number of points".
Mr Watson infuriated many Tory MPs when he rejected calls to apologise to the widow and family of Lord Brittan, the former Conservative cabinet minister who died in January without being told he had been cleared of a rape allegation.
Police originally decided no action should be taken but the investigation was reopened last year and Lord Brittan was interviewed while seriously ill.
Mr Watson came under intense scrutiny after a letter emerged in which he wrote to the director of public prosecutions Alison Saunders in April 2014 complaining at the way the case was being handled.
Speaking in the Commons last week, he insisted he was "right to demand the guidelines were adhered to" and that he was doing his duty by passing on information and pressing for an investigation.
He also made clear that he intended to continue championing the case of child abuse victims who had been too scared to speak out, adding: "If anyone deserves an apology it is them."
Assistant Commissioner Patricia Gallan and Deputy Assistant Commissioner Steve Rodhouse, both of the Metropolitan Police, are scheduled to give evidence at today's session.
Scotland Yard apologised to Lady Brittan earlier this month for failing to tell the family before the peer's death that he had been cleared of an allegation that he raped a 19-year-old woman in 1967.
Last week the Met published a detailed summary of a report into the matter and said a separate force has been asked to review the inquiry.
Ms Saunders will also appear before the committee.
The Crown Prosecution Service has previously stressed that it "at no point made any request to the Metropolitan Police Service (MPS) that they reopen their investigation into Lord Brittan in relation to complaints highlighted by Tom Watson".
It also pointed out that the peer was interviewed before it had forwarded the MP's letter to police.