LONDON – A burgeoning child molesting scandal with racial overtones going back 15 years threatens the government of Britain’s Labour Party prime minister, Sir Keir Starmer.

Barely six months after Labour won a majority in parliamentary elections that lofted him to national leadership, Mr. Starmer is fending off charges that he ignored and downplayed charges that gangs of immigrants mainly from Pakistan were “grooming” young girls for rape and prostitution.

Facing the worst attacks in his six months in office, Mr. Starmer blames the onslaught against him on Britain’s far right, fueled by the world’s richest man, Donald Trump’s pal and adviser, Elon Musk.

In response to Mr. Musk’s claim that Mr. Starmer was “complicit in the rape of Britain,” the prime minister said “those that are spreading lies and misinformation as far and as wide as possible – they’re not interested in victims.” Rather, as the British press reported, “They’re interested in themselves.” Sir Keir did not need to mention Mr. Musk by name when he held “the far right” as responsible for attacking him.

That argument, though, ran straight into refutations from Conservative Party leaders, sensing an issue that gets to the heart of British complexes and fears about immigrants from the subcontinent that Britain ruled as “the jewel of the crown” of its empire until August 15, 1947, two years after the Japanese surrender that ended World War II in Asia.

An English YouTube commentator, Carl Benjamin, charged that British authorities deliberately overlooked the reality that gangs of Pakistanis were largely responsible for raping women as young as 14 in the Manchester suburbs of Rochdale and Oldham and other towns. The government, he said on Lotuseaters.com, overlooked the specific role of Pakistanis in the interests of “multiculturalism” and “political correctness.”

Often, said Mr. Benjamin, official information leaflets and broadcasts focused on ethnically English men as perpetrating sexual offenses when, in fact, they were a small minority among offenders dominated by immigrants from South Asia. That claim struck a populist chord among Britons fed up with illegal immigrants mainly from the South Asian nations of India, Pakistan, Bangladesh, Nepal and Sri Lanka, pouring into Britain.

The numbers, arriving by boat across the English Channel, are, at 36,812 last year, minuscule compared to illegal immigration across America’s porous land borders. They are, though, enough to deepen the chasm in a class-ridden society historically divided along social and ethnic lines.

Conservatives, sensing the impact of the “grooming” issue, immediately jumped into the debate while omitting the “Pakistani” label in their public utterances. The “shadow” home secretary, Chris Philip, the Conservative who would be the home secretary were his party in power, said it was “disgraceful” that Sir Keir “is smearing people who are concerned about rape gangs as jumping on a ‘far right’ bandwagon,” the Daily Express reported. Rather, said Mr. Philip, the prime minister should be “facing up to his own record” and “reconsidering his refusal as PM to hold a full national inquiry.”

Sir Keir responded with aggrieved indignation to affronts against his record as head of the Crown Prosecution Service between 2008 and 2013, when, he said, he was among the first to go after gangs responsible for sexual crimes. “When I left office, we had the highest number of child sexual abuse cases being prosecuted on record,” the BBC quoted him as saying. “I changed the system because I could see some of the things that were going wrong.” He accused a succession of Conservative governments of avoiding the issue “for 14 long years” until Labour returned to power.

Much though Labour would like to get away from the subject, the Conservatives aren’t letting up. The Conservative leader, Kemi Badenoch, jumped in on Mr. Musk’s X — the same medium on which Mr. Musk launched his attack on the failure to take forceful action against gangs. Ms. Badenoch said the Tories — British for Conservatives — would introduce an amendment on Wednesday to the Children’s Wellbeing and Schools Bill mandating “a full national inquiry into the rape gangs grooming scandal.”

She was, she said, “serious when I said it’s time to get justice for victims … so we can do right by the victims and end the culture of cover-ups” — a direct jab at Mr. Starmer and Labour.