The prime minister has attacked politicians and activists for “spreading lies and misinformation”.
Billionaire Elon Musk has accused Sir Keir Starmer of being “complicit in the rape of Britain” for failing to tackle grooming gangs during his tenure as Director of Public Prosecutions (DPP).
Senior Conservative and Reform UK MPs also spent the week calling for a national inquiry into child sexual abuse.
But Sir Kerr said: “Those who are spreading lies and misinformation as far as possible are not interested in the victims, they are interested in themselves.”
He said the online debate had “crossed a line”, resulting in threats against MPs, including Defense Minister Jess Phillips.
Sir Keir accused the Tories of “jumping on the bandwagon” to gain attention.
He added that Conservative MPs were “pumping up the right-wing rhetoric” on child sexual abuse after 14 years of failing to act.
Describing child sexual abuse as “absolutely sickening”, Sir Kerr defended his record in office as DPP – saying he tackled the issue “head on”.
While DPP, Sir Kerr introduced a special prosecutor for child abuse and sexual exploitation to oversee convictions against grooming gangs.
It also changed Crown Prosecution Service (CPS) guidance to encourage police to investigate suspects in complex sexual assault cases and encouraged judicial reforms aimed at making the process less painful for victims.
“I changed the system because I could see some things that were going wrong,” he told reporters.
Sir Keir said he reopened the cases, the first prosecution of an “Asian grooming gang” in Rochdale and called for mandatory reporting of child sexual abuse.
“When I left office, we had the highest number of child sexual abuse cases on record,” Sir Kerr said.
“The victims here were subjected to horrific abuse, and then they were not heard,” he said.
They said Phillips had done “a thousand times more” to protect victims of child sex abuse than her attackers could “even dream of”.
Sir Kerr did not name any of those he believed were lying, but his comments sparked a series of questions about Musk.
Over the past week, the tech entrepreneur has used his platform on social media site X to attack the Labor government over the issue.
Musk accused Phillips of being a “rape genocide apologist” and called for him and Sir Kerr to be jailed.
On Monday, Musk launched a poll asking X users to vote on whether “America should free the people of Great Britain from their tyrannical government”.
Asked about the post, Sir Kerr chose not to respond.
Musk’s push to remove the prime minister could create a diplomatic dilemma for Labour.
In addition to being one of the richest men in the world, Musk is also a key adviser to US President-elect Donald Trump.
Musk has also used his platform to secure the release of far-right activist Tommy Robinson from prison.
Robinson, whose real name is Stephen Yaxley-Lennon, is currently serving an 18-month prison sentence for contempt of court. Admitting that he violated the injunction. He lost a contempt of court case against him in 2021 over repeated claims about a Syrian refugee schoolboy.
Sir Keir accused Robinson of “appeasing” those who were not interested in justice and said he would not tolerate debate and debate over lies.
“Once we lose that anchor that matters to the truth, to the robust debate that we should be having, then we’re on a very slippery slope,” he said.