The British government has spent in excess of 20 billion pounds ($29 billion) on fighting terrorism since September 11, 2001, according to officials figures released on Sunday.
The bulk of the money has funded military operations. But the government also forked out substantial sums for its diplomatic efforts and the reconstruction of Afghanistan and Iraq.
Britain spent 18 billion pounds on military operations, with cost mounting heavily in Afghanistan in recent years. By comparison, Britain's overall core annual defence budget is around 37 billion pounds.
The British Army has, meanwhile, bemoaned its 299 victims of the war in Afghanistan. A 21-year-old soldier was killed in the country's restive southern Helmand Province Friday.
Prime Minister David Cameron has called for more public support and appreciation for the country's armed forces, saying this was a "social responsibility".
Around 10,000 British troops are stationed in Afghanistan.