The Taliban yesterday served chilling notice on the governments of President Hamid Karzai, Britain and the United States that it still has the capability to strike at will, even in the heart of the most protected security zone in Kabul. The lethal demonstration at the height of Afghanistan's premier military parade cost the insurgents a handful of volunteers. It cost Karzai's already-fragile administration incalculable amounts in credibility and dignity in the scramble to flee the main reviewing stand. Bursts of automatic fire from rifles smuggled through checkpoints tore apart the illusion of central control of the Afghan capital in full view of the world's media. That failure of security will not go unnoticed by Nato member countries already reluctant to commit men and material to a campaign that could last generations and which has so far defied conventional definitions of victory or defeat. There have been predictions in recent weeks that the Taliban and allies were a spent force. Even seasoned British commanders have said that the 5000 insurgent casualties in 2007 would make a renewal of the traditional spring campaign a non-starter. Instead of courageous but doomed attempts to confront western troops head-on, the Taliban would resort to roadside bombs and individual suicide attacks. It is a prediction that may come back to bite those who should know better, as the infiltration of yesterday's celebration of the end of communist rule in 1992 proved.

The annual harvest of opium resin from poppy crops throughout Helmand and Kandahar provinces finishes in about two weeks. British, Canadian and US troops have enjoyed a period of relative winter calm as farmers collected the sticky by-product that will end up as bags of heroin on UK city streets. When the harvest ends, snowmelt clears the high passes, and the bundles of resin are shipped off to makeshift refineries on both sides of the Pakistan border, it will be time for Afghans to pick up the Kalashnikov again. Some will fight for pay and antipathy to "invaders", others out of commitment to hardline Islam.

The attack in Kabul should also be a timely reminder to the thousands of Scots soldiers who have just arrived in Helmand as a major part of Britain's garrison in the insurgent heartland that they must remain focused for every minute of every day for the next six months. Constant vigilance is the watchword. There are no second prizes in the latest version of the Great Game.