The Prime Minister made a brief statement in Parliament to which the Leader of the Opposition - Sir Keir Starmer - responded.
After Starmer spoke, Johnson referred to Starmer as a "former Director of Public Prosecutions"and continued - "... although he spent most of his time prosecuting journalists and failing to prosecute Jimmy Savile, as far as I can make out - chose to use this moment continually to prejudge a police inquiry..... "
Starmer was DPP - (the head of the Crown Prosecution Service) - from 1 November 2008 to 1 November 2013. The post of DPP has existed since the appointment of Sir John Maule QC who was DPP from 1880 to 1884. The Prosecution of Offences Act 1985 created the Crown Prosecution Service (CPS) and made the DPP its head.
In taking decisions to prosecute, the CPS applies both an evidential test (realistic prospect of conviction) and a public interest test - i,e. whether it is in the public interest to prosecute. Both tests can sometimes be difficult to apply and decisions taken by prosecutors, particularly in high profile cases, can be controversial.
It is true that a number of journalists were prosecuted during Starmer's time as DPP.
For example, Operation Elveden was a police investigation into allegations of inappropriate payments to Police Officers and other public officials. The Operation ran for 5 years and ended in February 2016. Most notably, 5 journalists were acquitted at the Old Bailey in March 2015. The charges against the 5 related to paying public officials for stories.
In 2013, Starmer introduced new legal guidelines aimed at giving greater weight to the public interest in reporting news when prosecutors are making charging decisions relating to journalists - The Guardian 18 October 2013. The latest guidance is on the CPS website.
The late Jimmy Savile (1926-2011) was a sexual predator over many years. He was thought to have committed hundreds of offences but was never prosecuted. According to a Justice Inspectorate report (link below), Savile's first known offence was in 1955.
As reported by The Independent 1 February 2022 - in 2009 the CPS decided not to prosecute Savile. According to reports at the time, the 2009 decision was taken on the basis of insufficient evidence but the decision was taken by a prosecutor in the CPS and not by Starmer personally.
See also FULL FACT - 26 June 2020
In October 2012, Starmer announced a review of the 2009 CPS decisions not to prosecute Savile regarding allegations going back to the 1970s. The review was conducted by Alison Levitt QC who reported in January 2013. At the time, The Guardian published this article about the review - Savile inquiry sparks widespread reassessment of abuse complaints | Police | The Guardian 11 January 2013
Levitt found that there was "nothing to suggest that the decisions not to prosecute were consciously influenced by any improper motive on the part of either police of prosecutors" but "having spoken to the victims I have been drive to the conclusion that had the police and prosecution taken a different approach a prosecution might have been possible."
The Levitt report led Starmer, as DPP and Head of the CPS, to apologise for "shortcomings" in the part played by the CPS in deciding not to prosecute some of the cases. The outcome was that Starmer proposed changes to the approach of police and prosecutors to credibility in sexual assault cases. The changes he put forward were noted in this article published by COUNSEL magazine -
Justice Inspectorate report 2013:
See also Giving Victims a Voice 2013
The Prime Minister's jibe was, to say the least, utterly unworthy even when account is taken of the fact that during the debate on 31 January he was akin to a cornered rat ! Starmer's time as DPP certainly included some highly publicised matters about which there was strong public opinion at the time but Starmer and the CPS discharged their duties properly.
1 February 2022
Addendum 8 February - The Independent - Johnson under pressure after Starmer heckled by mob outside Parliament (msn.com)