Sir Keir Starmer has said sex abuse allegations against Mohamed Al Fayed “never crossed” his desk during his tenure as director of public prosecutions.

The Prime Minister, who served as head of the Crown Prosecution Service (CPS) from 2008 to 2013, was questioned in the Commons as to why he “declined to instigate a prosecution for rape and sexual abuse” against the former owner of luxury department store Harrods.

More than 100 alleged victims have contacted police to say they were sexually abused by Mr Al Fayed, the youngest of whom is thought to have been 13 at the time.

A number of allegations were made against him while he was still alive.

Investigators twice sent files for a charging decision to the CPS, once in 2008 relating to three alleged victims and again in 2015 linked to one other.

During Prime Minister’s Questions – which was dominated by the clash between Sir Keir and Conservative leader Kemi Badenoch over a national inquiry on grooming gangs – Tory MP Sir Roger Gale raised the case of Mr Al Fayed.

The member for Herne Bay and Sandwich said: “The Prime Minister from that despatch box has made much of his service as the public prosecutor.

“So could he tell the House in that capacity, why during his time he declined to instigate a prosecution for rape and sexual abuse against Mohamed Fayed?”

Sir Keir replied: “That case never crossed my desk.”

The Prime Minister also faced attacks over his Treasury minister Tulip Siddiq, who he said has “acted appropriately” in referring herself for investigation following controversies over properties linked to her family.

Ms Siddiq, the niece of former Bangladesh prime minister Sheikh Hasina, has faced calls for an investigation following reports that she lived in properties in London linked to allies of her aunt.

Tory MP Gregory Stafford (Farnham and Bordon) referred to other Cabinet controversies relating to Rachel Reeves’ CV and former transport secretary Louise Haigh, who resigned in November over a fraud conviction dating back to before her time in Parliament.

He said: “First of all we had a Chancellor who embellished her CV, then we had a transport secretary with a fraud conviction, and now we’ve got an anti-corruption minister who is being investigated for corruption.

“Now, I know the Prime Minister likes living in free accommodation, but does he really think it’s appropriate that his minister is being given free housing by the political allies of some very dubious foreign regimes?”

Sir Keir replied: “We brought in our new Ministerial Code to allow ministers to establish the facts and I’m not going to give a running commentary on that.”

Elsewhere in the session Liberal Democrat leader Sir Ed Davey urged the Government to accelerate its planned reform of social care, as not doing so might lead to wider NHS reforms failing.

Sir Ed said family carers are “making huge sacrifices to fill the gap” in the NHS, as he asked the Prime Minister to ensure “2025 is the year we finally rise to the challenge of fixing care”.

Sir Keir highlighted “immediate action” the Government has taken to improve care, referring to £3.7 billion of additional funding in the autumn budget for social care, and £86 million to allow 7,800 more disabled and elderly people to “live more independent lives”.

As temperatures continue to drop across the country, the SNP’s Westminster leader asked Sir Keir whether he understands the public’s unhappiness over cuts to the winter fuel allowance.

Stephen Flynn said the winter fuel allowance has been “unacceptably taken away from so many vulnerable pensioners”.

The Prime Minister said “tough decisions” were needed in the Budget, but that Scotland had received “the largest settlement since devolution began”.

He added: “What it’s done is given the money so the SNP have the money, they have the power, and no more excuses for the non-delivery that we see in Scotland.

“If (Mr Flynn) wants me to reverse that he should say so.”