Frank Ledwidge, author of "Investment in Blood" has calculated that The war in Afghanistan has cost Britain at least £37bn and the figure will rise to a sum equivalent to more than £2,000 for every taxpaying household.
Since 2006, on a conservative estimate, it has cost £15m a day to maintain Britain's military presence in Helmand province. The equivalent of £25,000 will have been spent for every one of Helmand's 1.5 million inhabitants, more than most of them will earn in a lifetime.
British troops in Helmand have killed at least 500 non-combatants. About half of these have been officially admitted and Britain has paid compensation to the victims' families. The rest are based on estimates from UN and NGO reports, and "collateral damage" from air strikes and gun battles.
Helmand is no more stable now than when thousands of British troops were deployed there in 2006. Opium production that fell under the Taliban, is increasing, fuelling corruption and the coffers of warlords.
By 2020, the author of a new book says, Britain will have spent at least £40bn on its Afghan campaign, enough to recruit over 5,000 nurses and pay for them throughout their careers. It could fund free tuition for all students in British higher education for 10 years.
MoD officials said that British troops were in Helmand to protect British national security by helping Afghans build up their own security forces.
"...of all the thousands of civilians and combatants, not a single al-Qaida operative or 'international terrorist' who could conceivably have threatened the United Kingdom is recorded as having been killed by Nato forces in Helmand," Ledwidge writes.
It was a serious mistake, the author adds, to treat al-Qaida as a military problem – the problem was primarily an intelligence one. Reflecting the widespread view across Whitehall and among defence chiefs, he says the real reason Britain has expended so much blood and money on Afghanistan is simple: "The perceived necessity of retaining the closest possible links with the US."
The real beneficiaries of the war, he suggests, are development consultants, Afghan drug lords, and international arms companies. Much of British aid to Afghanistan is spent on consultancy fees rather than those Afghans who need it most.
Ledwidge explained: "Once the last British helicopter leaves a deserted and wrecked Camp Bastion, Helmand – to which Britain claimed it would bring 'good governance' – will be a fractious narco-state occasionally fought over by opium barons and their cronies."