Gordon Brown will today issue a vigorous defence of Britain's military mission in Afghanistan as he repeats warnings that the al-Qa'ida terror network poses the biggest source of threat to UK national security.
He will say that action against al-Qa'ida has had greater impact this year than in any 12-month period since the 2001 war to topple the Taliban, but will warn that the terror group continues to recruit and train and could return to Afghanistan if international forces pulled out.
The comments, in his annual Guildhall foreign policy speech, mark the latest stage in the Prime Minister's drive to shore up public support for the war, following a radio interview, a speech to military top brass and an address to the Commons in recent weeks.
They come a day after a poll in the Independent on Sunday suggesting that almost three-quarters of voters (71 per cent) want British troops withdrawn from Afghanistan within a year.
And they follow the death yesterday of the 96th British serviceman to be killed in Afghanistan this year - a soldier from 7th Battalion The Rifles who was shot while on foot patrol near Sangin in Helmand province.
Speaking at the Lord Mayor of London's Banquet, Mr Brown will reject an approach of "splendid isolation" and say that Britain needs a foreign policy that is both "patriotic and internationalist".
Britain can best defend its own national interests through international co-operation and "leading in the construction of a new global order", he will say.
The Prime Minister will warn that al-Qa'ida continues to run "an extensive recruitment network across Africa, the Middle East, western Europe and in the UK" to attract adherents to its brand of international terror.
"Several hundred" foreign fighters are still based in the tribal areas of northern Pakistan, bordering Afghanistan, and attending training camps to learn bomb-making and weapons skills.
And he will say that the group - headed by Osama bin Laden - continues to maintain links with both the Afghan and Pakistani Taliban.
"Vigilance in defence of national security will never be sacrificed to expediency," Mr Brown will say. "Necessary resolution will never succumb to appeasement. The greater international good will never be subordinated to the mood of the passing moment.
"So I vigorously defend our action in Afghanistan and Pakistan because al Qaida is today the biggest source of threat to our national security - and to the security of people's lives in Britain.
"And tonight I can report that more has been planned and enacted with greater success in this one year to disable al Qaida than in any year since the original invasion in 2001."
Setting out his summary of Britain's case for involvement in Afghanistan and Pakistan, the Prime Minister will say: "We are in Afghanistan because we judge that if the Taliban regained power, al Qaida and other terrorist groups would once more have an environment in which they could operate.
"We are there because action in Afghanistan is not an alternative to action in Pakistan, but an inseparable support to it."
Mr Brown will reject calls for Britain to pull out of the Nato-led International Security and Assistance Force (Isaf), bring its troops home and concentrate on protective measures to prevent terror attacks in the UK.
"At every point in our history where we have looked outwards, we have become stronger," he will say.
"And now, more than ever, there is no future in what was once called 'splendid isolation'.
"When Britain is bold, when Britain is engaged, when Britain is confident and outward-looking, we have shown time and again that Britain has a power and an energy that far exceeds the limits of our geography, our population, and our means.
"As a nation we have every reason to be optimistic about our prospects: confident in our alliances, faithful to our values and determined as progressive pioneers to shape the world to come.
"And that is why I say our foreign policy must be both patriotic and internationalist: a foreign policy that recognises and exploits Britain's unique strengths, and defends Britain's national interests strongly - not by retreating into isolation, but by advancing in international co-operation.
"I believe that Britain can inspire the world. I believe that Britain can challenge the world. But most importantly of all, I believe that Britain can and must play its full part in changing the world.
"And to do so we must have confidence in our distinctive strengths: our global values, global alliances and global actions; because with conviction in our values and confidence in our alliances, Britain can lead in the construction of a new global order."Reuse content