The Scotland Yard team will provide forensic and technical expertise but will not be allowed to go on a "wild goose chase and create a political disturbance," Musharraf told a news conference late Thursday.
Bhutto's killing on Dec. 27 plunged an already volatile Pakistan deeper into crisis as it battled a surge in violence by al Qaeda and Taliban extremists. It also forced a six-week delay in parliamentary elections, now set for Feb. 18, which were seen as crucial to restoring stability and democracy to this U.S. ally.
Musharraf, a former army chief who seized power in a 1999 coup, rejected accusations that a security lapse led to Bhutto's killing and suggested she was partly at fault because she poked her head out of her bombproof vehicle's sunroof after an election rally despite threats by Islamic extremists.
He acknowledged his decision to seek outside help to investigate the killing was partly to allay suspicions of government complicity. Bhutto had accused elements in the ruling party of plotting to kill her.
"Here's a situation where maybe we need to go beyond ourselves to prove to the world and our people here, who are emotionally charged, that we don't mind going to any extent, as nobody is involved from the government side or the agencies," Musharraf said.
The British officers declined to comment to reporters as they arrived at Islamabad airport Friday morning.
Rioting following Bhutto's death killed nearly 60 people and caused about $1.3 billion in damage in the worst-hit province of Sindh, authorities say.
The government quickly accused an Islamic militant of orchestrating the shooting and bombing attack on Bhutto and said she died from the force of the blast and not a gunshot wound. Many in this country of 160 million people, already skeptical of their government, questioned that account and Bhutto's party has demanded a U.N. probe.
Musharraf maintained Pakistan was capable of conducting its own investigation - saying it was no "banana republic" - but acknowledged the government may have erred in giving a precise cause of death just a day after Bhutto's killing although no autopsy was conducted.
"One should not give a statement that's 100 percent final. That's the flaw that we suffer from," Musharraf said, noting that more evidence was emerging into the attack. "We needed more experience, maybe more forensic and technical experience that our people don't have. Therefore, I thought Scotland Yard may be more helpful."
Iranian Foreign Minister Manouchehr Mottaki visited Islamabad to pay his condolences.
"Those who have done this crime have targeted the stability and security of Pakistan," he told reporters after visiting the headquarters of Bhutto's party. "Extremism and terrorism has no place in the minds and in the hearts of the people of this region."
He further conceded shortcomings in Pakistan's handling of the case, including the hosing down of the bomb site hours after the attack, widely seen as undermining a detailed forensic examination. But he dismissed any suggestion there was a plan to conceal evidence.
"I'm not fully satisfied. I will accept that: cleaning the area. Why did they do that? If you are meaning they did that by design I would say no. It's just inefficiency, people thinking things have to be cleared, traffic has to go through," he said.
Musharraf blamed Taliban militant leaders Baitullah Mehsud and Maulana Fazlullah, also believed linked to al Qaeda, for a wave of suicide attacks. The government has already accused Mehsud of orchestrating the Bhutto attack, which a Mehsud spokesman has denied. The government published what it said was a communications intercept in which Mehsud allegedly congratulated some of his henchmen.
The president, a key U.S. ally in the war on terror, said killing Mehsud - who in the intercept gave his location as a town in the lawless tribal region of South Waziristan - was no easy matter. It would require a division of troops and cause major civilian casualties, he said.
Still, Musharraf denied al Qaeda was getting stronger in Pakistan.
He said Pakistan needed political reconciliation to fight terror, and he hoped the elections would haul the country out of its current crisis. "This is the greatest threat Pakistan has and we have to have political reconciliation to fight it together," he said.