The Defence Secretary John Hutton today dismissed claims that US military commanders are unhappy with the performance of the UK armed forces in Afghanistan.
A flurry of recent reports have suggested that US top brass has been left unimpressed by some aspects of the British effort in the country, with the counter-insurgency tactics singled out for criticism.
But Mr Hutton said in an interview with the Financial Times: "I do not think that is fair, nor do I think that reflects the real view in the Pentagon and elsewhere.
"There is a very high level of regard for the contribution that UK forces have made in Iraq and Afghanistan."
He said the UK - whose armed forces have suffered 145 fatalities in Afghanistan since 2001 - was open to criticism as long as it was "fair".
But Mr Hutton added: "Our reputation is very important to us. We will very strongly defend it.
"We will defend it by begin open to criticism where it is fair.
"We will not change our tactics in Afghanistan on the basis of uncorroborated and unsourced gossip from people who don't have the courage to put their names to their remarks."
The comments from Mr Hutton - who will discuss the Afghanistan mission at a meeting of Nato defence ministers in Poland today - came as President Barack Obama revealed plans to send 17,000 more US troops to Afghanistan.
Foreign Secretary David Miliband yesterday welcomed the move, saying the extra forces would play an "important and positive role" in the campaign.
Some will be deployed in Helmand province, where UK soldiers have been engaged in fierce fighting with the Taliban.
Around 8,100 British servicemen and women are currently serving in Afghanistan.
Speaking on a visit to the troubled country last night, Mr Miliband said: "I think that there is a universal recognition that these extra American troops can play, and will play, an important and positive role, when they are aligned and allied with a strategy for economic development and political development."
He also pledged that Britain would keep its troop levels "under review" - although he stressed that the prospect of an increase had not been raised directly.
"In terms of the United Kingdom we represent about 12% of the troops in Afghanistan at the moment," Mr Miliband said.
"We have had no request to increase our number of troops but, of course, we always keep the number under review."
Mr Hutton said he will raise the issue of increased troop contributions from other countries during today's meeting in Poland.
The US currently has around 30,000 troops in Afghanistan.
Mr Hutton acknowledged a shortage of troops may have hampered progress in Afghanistan and said he would press the UK's European Nato allies to provide extra military resources.
He said Britain had not received a direct request from the US to provide additional soldiers and added that the UK was "playing above our weight" compared with other Nato members.
Mr Hutton told BBC Radio 4's Today programme: "There has been a very lively debate in Europe over the last few years about this.
"Our view has always been very clear that Nato needs to do more, the European members of Nato need to do more.
"There needs to be a fairer burden-sharing of responsibilities, particularly in those really hard areas where what we need are combat forces."
Asked whether a shortage of troops had led to less progress being made, he said: "I think that's probably right. I think what we have got to do is understand the mission-critical status of our campaign in Afghanistan.
"The jihadists do pose a fundamental threat to our way of life. We have got to meet that challenge and we should meet it on a number of levels."
Mr Hutton said no decision had been made about deploying extra troops from the UK, although he was looking at whether the UK could do more.
But, he added: "We are playing, certainly, above our weight in the campaign there, so my initial view is it is for others to make further contributions ahead of any extra contributions from the UK."
Mr Hutton said it was "absolutely essential" for the Afghan government to speed up the political process and improve reconstruction programmes.
In a criticism of Afghan president Hamid Karzai's administration, he said: "There's no doubt at all that the government in Kabul needs to do more.
"It needs to tackle the problem about corruption, it needs to deal with the problem about drugs which is a poison in Afghan society and making it very difficult for good governance to take hold across the country.
"These are areas where there has got to be change and improvement in Kabul and these are very much the messages we have relayed to president Karzai and his colleagues."