Downing Street has hit back at claims by Afghan President Hamid Karzai that the arrival of British troops made security in his country worse.
Downing Street says UK troops have shown "bravery and determination"
The Times reported that Mr Karzai blamed inadequate troop numbers in the southern Helmand Province for helping the Taleban regain its control.
A Downing Street spokesman said he "wouldn't accept" UK presence had helped insurgents to take hold.
He said UK troops had "suffered losses" to aid Afghanistan's development.
The Times said Mr Karzai, speaking at the World Economic Forum in Davos, Switzerland, told a group of journalists that "there was one part of the country where we suffered after the arrival of the British forces", referring to Helmand.
He said the mistake was allowing the US and the UK to replace the province's sitting governor.
"Before that we were fully in charge of Helmand. When our governor was there, we were fully in charge. They came and said, 'Your governor is no good.'
"I said 'All right, do we have a replacement for this governor; do you have enough forces?'" Mr Karzai said.
"Both the American and the British forces guaranteed to me they knew what they were doing and I made the mistake of listening to them. And when they came in, the Taleban came."
'Bravery and determination'
But asked if the UK would accept that British troops' presence had allowed the Taleban back in, Prime Minister Gordon Brown's spokesman replied: "Of course we wouldn't accept that.
"We are working alongside the Afghan government in order to drive out the Taleban from Helmand."
He said the UK's strength in Afghanistan had been to "work with the Afghan government and to extend the authority of the Afghan government throughout the province to allow economic and political development".
"And it's to that aim that our armed forces have suffered losses and shown great bravery and determination."
He added that the UK was working closely with the Afghan authorities to resolve "political and economic and military issues in Helmand".
Mr Brown and Mr Karzai were to meet in Davos for talks.
Mr Karzai had long talks with Gordon Brown in Kabul last month
The prime minister's spokesman said the meeting was expected to be brief and he stressed that the two leaders had long talks during Mr Brown's visit to Kabul last month.
Labour MP David Crausby, member of the Commons Defence Select Committee and who visited Helmand in September, told BBC Radio 4's The World at One that he agreed with Mr Karzai on troop numbers.
But he added that the finger of blame should not be pointed at Britain or the US.
"That's been the fault of some of our Nato allies who haven't provided the sort of support that they really ought to supply, and they haven't supplied the right number of troops in the difficult areas of Afghanistan," Mr Crausby said.
"Britain's done more than its share of providing troops in Afghanistan and it's taken on a very different, difficult region in Helmand province."