Keir Starmer was not informed when an investigator at the Crown Prosecution Service decided to drop a case against Jimmy Savile, sources have told the Guardian, despite the fact he led the institution at the time. The Labour leader was unaware that a prosecutor had closed the case into the notorious child sexual abuser in 2009, nearly a year after he took over as director of public prosecutions (DPP). He later reviewed the case in 2012 and came very close to rubber-stamping the original decision not to prosecute, before deciding at the last minute to commission his chief legal adviser, Alison Levitt, to conduct a formal inquiry. The controversy continues to dog Starmer more than a decade later, with the former prime minister Boris Johnson having accused him of “failing to prosecute” Savile and victims criticising the Labour leader’s lack of action in the case. Conservative officials are poring over Starmer’s record as a human rights lawyer and DPP for material to use against Labour in a general election campaign. This week the Daily Mail and the Daily Telegraph have reported on cases fought by Starmer as a lawyer, one involving trying to stop a pet alsatian being put down and another in which he argued successfully for the early release of an arsonist. However, it is arguably the Savile case that is most likely to capture the public attention, and about which the Guardian can now reveal the full details. Nazir Afzal, a former prosecutor at the CPS, told the Guardian: “Pretty much the first time I’ve seen him angry was when he commissioned the Levitt report. He was angry because he did not know. He wondered why the escalation process did not permit the case to be referred up to his office.” Another person who worked closely with Starmer at the CPS at the time said: “Keir knew nothing about it. We had a lawyer with a file with Jimmy Savile written on it … The reviewing lawyer was told there were several victims but that none of them were willing to attend court, so he closed the case. The reviewing lawyer should have asked for advice.” A spokesperson for Starmer declined to comment on individual cases. However, they said: “Keir Starmer made it his mission as director of public prosecutions to ensure that victims of crime received justice and that criminals were brought to book for their crimes. He is rightly proud of his record.” The Guardian has been through Starmer’s record as DPP, reviewing individual cases, reading official reports and speaking to about a dozen current and former colleagues. The findings shed light both on the attacks he might face in the heat of an election campaign and on how he might approach being prime minister should Labour win next year’s election. The investigation uncovered details of how Starmer also admitted the CPS had made mistakes over the Rochdale grooming case; how he rubber-stamped a report into undercover policing that was later shown to have significant gaps; and how he was so successful at pushing through rapid budget cuts that some believed he damaged the institution in the longer term. Some critics say he was cautious in challenging police decisions and overly concerned with avoiding controversy, with some even speculating he had half an eye on his future political career. Several others praised Starmer’s management of the CPS and his decision-making skills, saying he went to great lengths to support colleagues who were under pressure and was willing to overhaul the organisation’s decision-making processes when they were found to be lacking. The most telling episode, both in terms of Starmer’s approach to leading large institutions and the political attacks that were to follow, was the controversy over the decision to close the Savile case in 2009. It first came into the public spotlight when Boris Johnson, the then prime minister, accused the Labour leader of “failing to prosecute Jimmy Savile”. Johnson’s comments provoked anger on the Labour benches and were cited by his policy chief, Munira Mirza, as the reason for her subsequent resignation. The Guardian’s investigation has uncovered the most detailed explanation yet for how Starmer’s CPS came to drop its case into Savile in 2009. Sources who spoke to the Guardian said Starmer inherited a sprawling network of prosecutors and lawyers who operated largely independently from the DPP’s office. Cases were often not referred up to senior leaders, even if decisions could have been politically sensitive. Starmer had recognised the problems this could cause him as DPP and appointed Levitt as his principal legal adviser in 2009. He gave her a remit to monitor and advise on any case which could prove contentious, including anything which involved the reckless transmission of HIV and anything that involved granting immunity from prosecution. Neither Starmer nor Levitt were aware of the decision taken by the prosecutor to close the Savile file in 2009, after which the CPS records were destroyed. One person involved at the time said the prosecutor should have asked more questions about why the victims were not willing to testify and whether anything could have been done to persuade them to. However, the person added that it was unsurprising that given the evidence in front of them they decided not to take further action. Starmer reviewed the case again in late 2012 after allegations about Savile became public. One person who worked with him at the time said he was about to close the file again when he decided instead to ask Levitt to look into it one more time. The colleague said Starmer told them: “This case is nagging at me. I’m going to go public tomorrow and say we’ve reviewed this and I believe the decision is fine, but I want Alison to take one last look at it.” Levitt then conducted a full inquiry into the case in which she found that not only had the CPS made mistakes in the Savile case but that is was likely to have mistakenly dropped many similar sexual assault complaints. In response the CPS changed its guidance on how prosecutors should deal with accusations of sexual abuse – changes that were to have a lasting effect on how serious cases were dealt with. The controversy also had a lasting effect on Starmer. Those close to him say it helped formulate his views on how closely he needed to monitor such a large and decentralised organisation – a style of leadership that allies and critics say he has brought with him to the Labour party. One person who has worked with him said: “If you think Keir is a control freak now, that has its roots in the Savile case and his early days in the CPS. That’s when he realised how hard he needed to work to ensure consistency across a large organisation.”