The British government said it would amend a decades-old law as a first step toward deporting Shabir Ahmed, who served 14 years in prison for raping and trafficking teenage girls in Northern England as the leader of a “grooming gang.”

Mr. Ahmed was convicted of rape, sexual assault and trafficking in Rochdale and Oldham, in northwest England, in two separate court cases in 2012. The leader of a sexual exploitation ring involving mostly Pakistani men, he was sentenced to a term of 19 years and stripped of his British citizenship while in prison.

But when he was released earlier this month after serving the mandatory amount of his sentence, officials said he could not be deported to his birth country of Pakistan. The government is barred from deporting him under provisions in a 1971 immigration law aimed at protecting Commonwealth citizens who had arrived in Britain before 1973 from deportation.

In remarks to Parliament on Monday, Shabana Mahmood, the home secretary, said that law would be changed.

“Our amendment will provide the home secretary with a new power to disapply Section 7 of the Immigration Act 1971 for serious criminals,” Ms. Mahmood told lawmakers Monday evening. “This provides protections for long-term U.K. residents, but clearly should not be acting as a bar against removal in cases like that of Shabir Ahmed.”

The amendment would theoretically allow the government to deport Commonwealth citizens who commit serious crimes and who would otherwise have been protected by the 1971 law. It follows widespread outrage from the country’s leading political figures about the fact that Mr. Ahmed has been freed to live in Britain.

In her comments, Ms. Mahmood said that only people like Mr. Ahmed, who had their citizenship stripped because of the severity of their crimes, could become eligible for deportation at the discretion of the home secretary.

But Ms. Mahmood and other government officials cautioned that changing the law would not guarantee Mr. Ahmed’s departure from Britain. In order to deport immigrants, their home countries must be willing to accept them back. So far, Pakistan has refused to allow Mr. Ahmed back in the country.

“It is important to note this does not guarantee his removal from this country,” she told her colleagues, adding that the government would “continue to work all avenues to pursue a deportation.”

“I know the thoughts of everyone here are with the victims and survivors of this vile criminal,” she added.

British officials said the government had been in touch with Pakistan to urge the country to take Mr. Ahmed back. They declined to say whether Britain might threaten to stop issuing visas to Pakistanis wanting to enter Britain unless Mr. Ahmed is accepted back in the country. But officials said that they were looking at “all options” to deport him.

On Monday, Catherine Atkinson, the victims minister, told the BBC that the home secretary had used the threat of visa sanctions against other countries to convince those countries to accept people deported from Britain.

“She threatened visa penalties for Angola, Namibia and Democratic Republic of Congo unless they took back illegal immigrants, and four months later all three were cooperating, with flights off the ground,” Ms. Atkinson said of Ms. Mahmood.

More than a decade ago, Mr. Ahmed became one of the faces of the country’s “grooming gangs” scandal, in which groups of men were accused of systematically exploiting vulnerable young girls. The police were accused of moving too slowly to confront the crimes, leading to political inquiries and years of angry recriminations about race and policing.

Most of the perpetrators convicted in the grooming gang cases were of Pakistani descent and most of the victims were young and white.

In Rochdale, Mr. Ahmed, a father of four and a delivery driver for takeout restaurants, was convicted of luring young runaways and other teenagers looking for food and shelter. He would tell them, “Call me Daddy.”

During his trial in 2012, Mr. Ahmed showed no remorse and called the judge in the case a “racist bastard.” He repeatedly said that the girls whom he had raped were “prostitutes” and that white people in Britain had trained their daughters to drink and be sexually promiscuous at an early age. But he was also convicted, that same year, of 30 counts of child rape involving a Pakistani girl living in Britain whom he had abused over a decade.