Prime Minister David Cameron has defended his comments about Pakistan's record on tackling terrorism as he completed his trip to India.
At a press conference with Indian counterpart Manmohan Singh, he said no-one was in "any doubt" there were terrorist groups operating in Pakistan.
The Pakistan government had made real progress but must do more to "crack down on and eliminate" them, he said.
He said he was "looking forward" to talks with Pakistan's president.
President Asif Ali Zardari's visit to the UK next week is likely to be dominated by the fallout from Mr Cameron's trip to India where he warned Pakistan about "promoting the export of terror" and being allowed to "look both ways" on the issue.
'Eliminating threat'
His remarks were criticised by Pakistani officials and led to him being accused of "damaging the prospects of regional peace".
In his last official engagement of the trip - a press conference with Indian Prime Minister Singh - Mr Cameron again stood by his remarks.
"We should be fair to the Pakistan government that they have taken steps in recent years to combat some of the terrorism in their own midst," he said.
"But we need to go on encouraging this action to take place so we can reduce and eliminate the threat of terrorism, whether here in India, Afghanistan or on the streets on London."
Asked whether he would be similarly candid when he met the Pakistan president in Britain next week, Mr Cameron said he would.
"I think the right way is to discuss these things frankly, openly and clearly. I look forward to having discussions next week, including with the Pakistan president."
Earlier, he told the BBC that speaking frankly about the issue was "what people expect of their government".
His remarks followed the leaking of US documents on the Wikileaks website in which Pakistan's Inter Services Intelligence agency was accused of secretly helping the Afghan insurgency.
'Enormous role'
Pakistan's High Commissioner to the UK, Wajid Shamsul Hasan, criticised Mr Cameron for choosing to believe leaks that the official said lacked both credibility and corroboration.
Writing in the Guardian, he said: "One would have wished that the prime minister would have considered Pakistan's enormous role in the war on terror and the sacrifices it has rendered since 9/11.
Later, Mr Hasan told the BBC that he hoped Mr Cameron's comments were a "slip of the tongue" and "not a meant slight by him".
Pakistani Foreign Ministry spokesman Abdul Basit told a news briefing that the government was "saddened" by his comments.
"These remarks are contrary to the facts on the ground," he said.
Referring to the Wikileaks disclosures, he added: "This malicious campaign that has been going on now for years against Pakistan and against our security agencies - particularly ISI - cannot belittle our achievements and cannot blight our record against militants and violent extremists."
The BBC's Sanjoy Majumder said Mr Cameron had "certainly made an impression with his comments on Pakistan, which were being seen as unusually blunt".
And Shadow Foreign Secretary David Miliband said the prime minister needed to think "through carefully what he is going to say" on such occasions.
While Britain must speak with "conviction" on important issues, he said Mr Cameron had only told "half the story" and "failed to recognise" Pakistan had lost thousands of its own citizens, including former leader Benazir Bhutto, to terrorist attacks.
"There is a fine line between a straight talker and a loud mouth," he told the BBC.
Nuclear deal
Mr Cameron's remarks are likely to be welcomed by officials in Delhi, which has long accused its neighbour of backing attacks on Indian targets.
The two nuclear-armed rivals have fought three wars, with peace negotiations stalling following the Mumbai attacks of 2008, which India blamed on Pakistani-based militants.
At the end of a trip designed to boost trade links, Mr Cameron spoke of an "enhanced and enduring" relationship between the two countries.
The UK has signed a multi-million pound defence deal with India and will be able to export British civil nuclear technology to India for the first time.
Indian premier Mr Singh said the two countries were "natural partners" and announced that they had reached partnership agreements in areas spanning energy, education, culture and the economy.