Prime Minister Gordon Brown defended Britain's military mission in Afghanistan today, insisting "we cannot, must not and will not walk away".
In a high-profile speech in London, hastily arranged following a series of British deaths in Afghanistan this week, Mr Brown said the military action in the country was "our first line of defence" against terror attacks at home.
Paying tribute days ahead of Remembrance Day to the 93 British troops who have died in Afghanistan this year, the Prime Minister said: "These men are our heroes today."
Mr Brown acknowledged that Britain's strategy was not "without danger or risk".
But he warned that al-Qa'ida terrorists continue to plot terror attacks on Britain from the region, and said: "This mission must not fail."
Mr Brown's speech comes amid polling evidence suggesting that a growing majority of voters now want to see British troops withdraw from Afghanistan within the coming year - with more than half in a survey this week saying they did not believe victory against the Taliban insurgents was possible.
And it follows a call from former Foreign Office minister Kim Howells for the mission in Afghanistan to be halted and the money spent on anti-terror measures in the UK.
In a clear response to Dr Howells' call, Mr Brown said he rejected any suggestion that the commitment in Afghanistan was diverting effort away from security at home.
"Britain has consistently shouldered its fair share of the burden and more - especially in the last three years, since we deployed into Southern Afghanistan, the heartland of the Taliban," he said.
"But when the main terrorist threat facing Britain emanates from Afghanistan and Pakistan; and when, although the sustained pressure in Pakistan, combined with military action in Afghanistan, is having a suppressive effect on al Qaida, we know that they continue to train and plot attacks on Britain from the region ... this mission must not fail.
"It is not easy; the choices are not simple. There is no strategy that is without danger and risk.
"But that is the responsibility of leadership - of government, and of our armed forces. To do what is necessary, however difficult, to keep the British people safe. We cannot, must not and will not walk away."
Mr Brown said that in discussions over the past few days, he had agreed a set of measures with Afghanistan President Hamid Karzai to improve the country's security, governance, political settlement, economic development and relations with neighbours like Pakistan.
He warned today that if Mr Karzai's government failed to fulfil these requirements, "it will have forfeited its right to international support".
Admitting that the evidence of fraud which overshadowed Mr Karzai's re-election was a "setback", Mr Brown warned: "I am not prepared to put the lives of British men and women in harm's way for a government that does not stand up against corruption."
Mr Brown said the key to bringing British troops home from Afghanistan was building up the home-grown armed forces and police to a state where they could deliver security themselves.
Despite the murder this week of five British servicemen by a "rogue" Afghan police officer they were training, the UK would not give up its role of training and mentoring local security forces.
"We will not give up this strategy of mentoring," said Mr Brown. "Because it is what distinguishes a liberating army from an army of occupation.
"Not an army in opposition to local Afghan people but an army supporting local Afghan people."
In an apparent acknowledgement of criticisms that he has not successfully explained his strategy in Afghanistan to voters, Mr Brown concluded: "What people here in Britain ask for is the same as our forces on the ground ask for - a clear sense of what success in Afghanistan would look like, and how we will get there.
"My answer is: we will have succeeded when our troops are coming home because the Afghans are providing security themselves, continuing the essential work of denying the territory of Afghanistan as a base for terrorists.
"The right strategy - for Britain and for the international community as a whole - is the one that enables the Afghans to take over from international forces sooner; at a higher level of capability; and with a greater level of assurance that the pressure on al-Qa'ida and other terrorist and extremist groups will be maintained, and so that a safer, more stable and better-governed Afghanistan will contribute to a safer Britain - in a safer world."
Mr Brown said he hoped Mr Karzai would use his inauguration speech on 19 November to set out in detail plans to fight corruption, build up his security forces and improve the governance of his country.
In a clear criticism of Mr Karzai's performance since he became president in 2004, the PM said the Afghan government had become "a byword for corruption".
He said he wanted a high-level international adviser to be sent to Afghanistan to help in the fight against corruption and warned the president that "cronies and warlords should have no place in the future of Afghanistan".
Mr Brown made clear continued allied support for Mr Karzai's administration - including the additional 500 troops he has approved in principle - would be dependent on his delivery of reform.
"International support depends on the scale of his ambition and the degree of his achievement in five key areas: security, governance, reconciliation, economic development and engagement with its neighbours," said Mr Brown.
"If with our help the new government of Afghanistan meets these five tests, it will have fulfilled an essential contract with its own people. And it will have earned the continuing support of the international community, despite the continuing sacrifice.
"If the government fails to meet these five tests, it will have not only failed its own people, it will have forfeited its right to international support."
The Prime Minister indicated that the process of political reconciliation should include reaching out to those who have previously fought the international coalition and Mr Karzai's government, so long as they give up violence.
Commending Mr Karzai's move to reach out to his defeated presidential rival Abdullah Abdullah, Mr Brown added: "More challenging still is to reach out to those who have been outside the political process.
"Reconciliation and reintegration are central to future security stability and prosperity. So there needs to be an agreed process for bringing those who reject violence back into the political fold."
Mr Brown said the Taliban had "failed" in its efforts to defeat the international coalition through conventional warfare, and had resorted instead to insurgent tactics in the hope they could "undermine morale and erode public support at home and persuade us to give up before the Afghan people get to see the benefits of legitimate governance or share in the benefits of greater prosperity".
UK troops needed to switch their strategy from straightforward counter-terrorism to more complex counter-insurgency work, which included building support among the local population and building the capacity of home-grown security forces.
Mr Brown insisted that "our presence in Afghanistan is justified and... our strategy, set out in the spring, is the right one".
He added: "We have not chosen the path of training and mentoring the Afghan forces because it is an easier or safer alternative - often it is the opposite - but because it is the right strategy.
"The Taliban and others who seek to undermine the work our forces are doing will not divert us from our strategy."
Mr Brown said he wanted to pay a personal tribute to all UK service personnel killed and injured in Afghanistan and compared them with the dead of the First and Second World Wars who will be remembered in services across the country on Sunday.
"Just as in the past we learnt of the bravery and sacrifice of British soldiers in the First and Second World Wars; in their fight to protect freedom both in our nation and the world; so our children will learn of the heroism of today's men and women fighting in Afghanistan - protecting our nation and the rest of the world from threat of global terrorism," said the Prime Minister.
"Fighting there, so that we are safer at home. Joined by countries from all over the world so that terrorism can be combated: a campaign of 43 countries prosecuted out of necessity, not of choice."
Mr Brown was speaking to an audience of high-ranking military figures at the Royal College of Defence Studies in London's Belgravia.
Before the 30-minute speech he spent time chatting informally with the course's college members - the majority of whom are colonels and brigadiers or equivalent rank.
He followed the lecture with a private question and answer session where he undoubtedly faced careful questioning from some of the military's most senior officers.Reuse content