Benzir Bhutto’s son warned yesterday that Pakistan may fall apart unless upcoming elections are “free and fair.”

Bilawal Bhutto Zardari, a 19-year-old student at Oxford who was appointed chairman of his mother’s Pakistan’s People’s Party after her assassination last month, spoke in London for the first time since returning from Pakistan to resume his studies.

“I fear for my country,'” he said. “I fear that if free and fair elections are not held, it may disintegrate.”

Acknowledging that he felt nervous while addressing the British press, he went on to speak with increasing composure on the day that elections had originally been scheduled to take place in Pakistan. The polls were postponed for six weeks until February 18 following the outrage after his mother’s murder.

Responding to questions about the risk to his own safety, he cited a PPP slogan: “How many Bhuttos can you kill? From every house, a Bhutto will come.”

He also reiterated demands for an independent investigation into his mother’s death.

“The family’s and party’s request is for a U.N.-sponsored investigation, because we do not believe that an investigation under the authority of the Pakistan government has the necessary transparency,” he said.

Mr. Bhutto Zardari wishes to resume studying history as an undergraduate at Christ Church. He said he had barely been at university eight weeks and was “just settling in” when his mother was assassinated in a shooting and suicide bomb attack in Rawalpindi. “When I am at Oxford, I hope that I can be left alone,” he said. He said he was more “resilient” since his mother’s death and paid tribute to her courage. Referring to her as shaheed — a martyr — he said, “Politics is also in my blood, and although I admit that my experience to date is limited, I intend to learn.”

Worries about his safety would not, he said, dissuade him from entering politics. Asked if he feared assassination, he said, “I fear more for my privacy.”

Despite his advisers’ insistence that he was “not a politician,” Mr. Bhutto Zardari has assumed the role as the political figurehead of the Bhutto dynasty that controls the country’s most popular party. He showed characteristic Bhutto ability to command an audience and fended off unwanted questions with ease, included a testy barrage from the BBC’s Jeremy Paxman.

He defended his appointment as his mother’s successor and rejected the journalist’s suggestions that his succession was undemocratic.

“It wasn’t handed on like some piece of family furniture. They asked me to do it, and I did,” he said. “Pakistan was burning, and we needed to show a united front. It was a moment of crisis, and we needed to stop the violence.”

He said the precedent of continuing the “bloodline” had been set after the execution of his grandfather, Zulfikar Ali Bhutto, when his grandmother, Nusrat, became chairman.

Mr. Bhutto Zardari also denied that his father’s image would damage the party, saying his father had served more than 11 years in jail. He added that his father, Asif Ali Zardari, would not stand for a seat in Parliament.

A lawyer representing the Pakistani government said the nation would pursue Asif Ali Zardari, for $49 million it alleges that he and his wife illegally hid in bank accounts in Switzerland following their time in power when she was prime minister in the 1990s. Mr. Zardari denies the allegations.

Finally, showing a flash of his mother’s steel, Mr. Bhutto Zardari took a swipe at America and President Musharraf. “I believe that dictatorships breed extremism,” he said. “Once the U.S. stops supporting dictators, we can successfully tackle extremists.”