The allied war in Afghanistan began in late 2001, which means that British involvement lasted for more than 13 years.
The duration of the conflict, which began after the September 11 2001 terror attacks in New York, is considerably longer than American combat in the Vietnam war from the mid 1960s to the mid 1970s.
Yesterday Britain’s armed forces who fought and died in Afghanistan were honoured by the Archbishop of Canterbury at a service at St Paul’s Cathedral, attended by the Queen and Duke of Edinburgh, the Prime Minister David Cameron, and other senior royals, politicians and military figures.
Also present was the prime minister when military action was launched, Tony Blair, who admits that he did not foresee how long the struggle against the Taliban would last. Almost 150,000 UK personnel were deployed, of whom 453 died.
Mr Blair has come under increasing attack for his role in the Iraq invasion of 2003. But the Afghan war was different. There was near unanimous support for it after the felling of the Twin Towers. It would have been inconceivable to allow the regime that harboured the bombers to stay in place.
Securing lasting peace in Afghanistan was an almost impossible task, but the fight itself was unavoidable.
Since 2001 the UK has been united in respect for the heroism of those who died or were injured. Many of those who were maimed were in the prime of their lives and yet have responded to losing limbs with good grace and determination.
Their bravery is humbling to the rest of the population, the great majority of whom have never put themselves in harm’s way on behalf of the country’s security.
It is all the more so, given how comfortable life is for the civilian population of Britain in 2015, in comparison to those whose lives are at daily risk from landmines or enemy attacks.
The Archbishop, the Most Rev Justin Welby, spoke for the nation when he described yesterday as “a moment for us to say thank you”.