Foreign Secretary David Miliband said Saturday that soldiers in Afghanistan were involved in a battle "for the future of Britain" after the British death toll surpassed that for the Iraq war.
Miliband said Britain would not be secure until it had established security in Afghanistan and it was vital to prevent the country again becoming an "incubator for terrorism" and a launch pad for attacks on the West.
Eight deaths were announced on Friday in one of the worst days for British forces in Afghanistan since the start of operations in 2001.
It took the total so far this month to 15 and raised the number of British servicemen who have died on operations in Afghanistan to 184, higher than the 179 who died in Iraq following the 2003 US-led invasion.
Miliband said it had been a "grievous few days" for the families of the dead, for the British army, and for the whole country.
"We know that they are engaged in a very, very difficult mission and we have a responsibility to engage the country in understanding that mission and supporting it," he told BBC radio.
"This is about the future of Britain because we know that the badlands of Afghanistan and Pakistan -- that border area -- have been used to launch terrible attacks, not just on the United States, but on Britain as well.
"We know that until we can ensure there is a modicum of stability and security provided by Afghan forces for their own people, we are not going to be able to be secure in our own country."
The head of Britain's military, Air Chief Marshal Jock Stirrup, insisted that Taliban insurgents were losing the fight against British and NATO-led forces in the volatile southern province of Helmand.
"It's tough going because the Taliban have rightly identified Helmand as their vital ground," Stirrup said in a televised statement on Friday.
"If they lose there then they lose everywhere and they are throwing everything they have into it. But they are losing and our commanders on the ground are very clear of that," he said.
"But it's going to take time and, alas, it does involve casualties."
The British death toll has increased sharply since its troops launched Operation Panther's Claw three weeks ago, a major assault against Taliban insurgents in Helmand.
Britain raised its troop presence in Afghanistan to 9,000 ahead of elections in August, with the vast majority in Helmand.
The United States has poured thousands of extra troops into Helmand.
Prime Minister Gordon Brown said the soldiers were facing a "very hard summer" and warned of more losses to come, but said it was vital the international community maintained its commitment to Afghanistan.
Among the eight deaths announced Friday were five soldiers from The 2nd Battalion The Rifles who were killed in two separate explosions while on the same patrol near Sangin in Helmand.
Most British deaths in recent months have come from powerful roadside bombs, the Taliban's weapon of choice.
The Times newspaper said Saturday that the rising casualties "prompt the fear that Afghanistan is becoming a quagmire."
"But Britain's interests lie in defeating the Taliban and helping to build a stable state," it said.
Amid claims from former heads of the army that British forces in Afghanistan lack enough helicopters, the parents of an 18-year-old soldier killed there accused the government of failing to give troops the resources they need.
Trevor and Jane Ford, whose son Private Ben Ford was killed in an explosion two years ago, said: "How much money do we need to throw at other things in this country before we realise the armed forces need that cash?
"What is Gordon Brown doing? Is he just sitting there counting his own money and leaving us to just dwindle along?" she said on BBC radio.