Gordon Brown has told the BBC that Pakistan must do more to "break" al-Qaeda and find Osama Bin Laden.
Questions must be asked about why nobody had been able "to spot or detain or get close to" the al-Qaeda leader, the prime minister said.
He said he wanted to see "more progress in taking out" Bin Laden and his second-in-command, Ayman Zawahiri.
Meanwhile, a US Senate report claims US forces had Bin Laden "within their grasp" in Afghanistan in late 2001.
BBC World Affairs correspondent Mike Wooldridge said this was not a new claim.
However, he said, staff working for the Democratic majority on the Foreign Relations Committee now claimed to have evidence that in December 2001 US military power was kept on the sidelines while Bin Laden escaped "unmolested" into Pakistan's unregulated tribal areas.
The report comes days before US President Barack Obama is due to announce additional US troops for Afghanistan - Mr Brown is to announce whether conditions have been met to send an extra 500 British troops.
Speaking in a BBC interview, the prime minister said that if so much effort was going into building up security in Afghanistan, Pakistan had "to be able to show that it can take on al-Qaeda".
The prime minister said Pakistan had made progress against the Taliban in south Waziristan.
We want to see more progress in taking out these two people at the top of al Qaida
But he told the BBC: "We've got to ask ourselves why, eight years after September the 11th, nobody has been able to spot or detain or get close to Osama bin Laden, nobody's been able to get close to Zawahiri, the number two in al-Qaeda."
Pakistan had to "join us in the major effort that the world is committing resources to, and that is not only to isolate al-Qaeda, but to break them in Pakistan", he said.
Pakistan's prime minister, Yousuf Raza Gilani, will meet Mr Brown at Downing Street on Thursday. Mr Brown informed Pakistan's president, Asif Ali Zardari by telephone that he intended to speak out about the hunt for Osama Bin Laden.
The prime minister told the BBC that over eight years "we should have been able to do more ... to get to the bottom of where al-Qaeda is operating from".
Progress had been made he said, but Pakistan had to make sure that "in South Waziristan we are taking on al-Qaeda directly".
"We want, after eight years, to see more progress in taking out these two people at the top of al-Qaeda, who have done so much damage and are clearly the brains behind many of the operations that have hit Britain," said Mr Brown.
Later Foreign Secretary David Miliband said Britain wanted Pakistan to "join us in upping our game" in tackling terrorism on its border with Afghanistan.
"We know that the Pakistani authorities, as the prime minister said, are taking big losses in their drive against the so-called Pakistan Taliban... we recognise that."
But he said it was "right that we recognise that stability in Afghanistan requires stability in Pakistan too and that requires a combined effort."
"We've all got to do more, Pakistan has got to do more, Afghanistan has got to do more and the international community has got to do more, but we've also got to do better."
In an interview with the BBC's Hard Talk programme due to be screened on Tuesday, Pakistan's foreign minister Shah Mahmood Qureshi said: "I can't speak for the last seven years, but I can certainly speak for the present government, which came into office in 2008.
"The democratically elected government of Pakistan has shown a resolve and determination to take the militants on.
"And I think today there's a great recognition of that, by the US, the Europeans, all over the world. There is an acknowledgement that Pakistan today is determined to fight the militants."
Shadow defence secretary Liam Fox told BBC One's Politics Show that Pakistan faced economic and political problems and its army did not "really have the capabilities for the sort of anti-terrorist counter-insurgency measures that we want".
"The international community has to give Pakistan a lot of help if Pakistan is to fulfil the role we want it to do," he said.
And Edward Davey, for the Liberal Democrats, said: "The real questions are, why hasn't this happened before and because it hasn't, why is it suddenly going to happen now?
"This looks more like wishful thinking than a new well considered strategy"
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