Gordon Brown yesterday demanded more action from Pakistan to find and “take out” al Qaida leaders Osama bin Laden and Ayman Zawahiri.
The Prime Minister made little attempt to hide his frustration at Pakistan's failure, eight years after the September 11 attacks in the USA, to track down the men responsible, who are believed to be hiding out in the north of the country.
Mr Brown's call came ahead of talks in Downing Street with Pakistan's prime minister Raza Gilani on Thursday.
He will give further details when he makes a statement to MPs this week setting out his strategy for the Afghanistan campaign, including his assessment of whether the conditions have been met to send an extra 500 troops, taking the total to 9,500.
US President Barack Obama is due to make his own long-awaited response to military calls for tens of thousands of reinforcements on Tuesday.
Number 10 said Mr Brown informed Pakistan's president Asif Ali Zardari on Saturday in a telephone conversation that he intended to speak out.
Some 30,000 Pakistani troops have been sent to South Waziristan as part of a drive to take on the Taliban in Pakistan, but Mr Brown made clear he wants them also to target the leadership of al Qaida, who have evaded international forces since the invasion of Afghanistan in 2001.
The Prime Minister said: “The Pakistan Government has started to take on the Taliban and to take on al Qaida in South Waziristan, but we have got to ask ourselves why, eight years after September 11, nobody has been able to spot or detain or get close to Osama bin Laden, nobody has been able to get close to Zawahiri, the number two of al Qaida.
“We have got to ask the Pakistani security forces, army and politicians to join us in the major effort that the world is committing resources to, not only to isolate al Qaida but to break them in Pakistan.”
Afghanistan’s High Commissioner in London Wajid Shamsul Hasan said it required more help from the UK and the international community to find the terror leaders.