Yesterday's suicide bomb on a police bus in the heart of Kabul was one of the deadliest since the Taliban was ousted from Afghanistan in 2001. The scale of the carnage ensured the kind of headlines that the Taliban has been desperate to achieve to bolster its case that the government and the Nato-led forces have lost control of the country. Although final numbers are in dispute, it seems that at least 35 people were killed, 22 of whom were police instructors, and many others injured. There can be no doubt that it was a successfully targeted attack on a bus taking police officers to their beats, with the bomber boarding when it stopped to pick up additional officers.

With more deaths and injuries among civilian bystanders prevented only by the fact the police bus was blocked by another bus, the insidious effect of such attacks is also bolstered, making ordinary people scared of the police, because they fear an attack.

With Nato-led forces reporting that they had repelled incursions by the Taliban in their spring offensive in Afghanistan, there was a tendency to refocus our attention on Iraq, but this fifth suicide attack in three days - the first four having already killed 14 people - is the grimmest of reminders that the Taliban forces have also been looking to Iraq and al Qaeda.

The group scarcely needs confirmation of the effectiveness of suicide bombing. In its long battle to oust the elected government of President Hamid Karzai, the tactic first killed at least 26 people and wounded 150 in a car bombing in Kabul in 2002. The years since have seen a series of suicide bombs; just a month ago three blasts in one day killed 21 police officers.

All this is on top of increasing casualties among the foreign troops, the British contingent of which is fighting in particularly difficult terrain in Helmand province. According to a senior British Army surgeon, injured soldiers face a delay of seven hours in reaching a field hospital. Lt Col Paul Parker lays the blame for delays - in both Afghanistan and Iraq - on a lack of dedicated helicopter ambulances and too many layers of command. This is a variation on the complaints we have heard before about the shortage of specialist equipment for the task we have dispatched our armed forces to carry out.

This must be properly addressed. The least we can do for the people who put their lives on the line for the betterment of the world is to give them the best possible chance of survival: that means an effective command structure as well as enough vehicles without having to borrow them from the Estonians or others. That the MoD is to provide 14 additional helicopters for Afghanistan over the next two years is welcome news, but a salutary reminder that there will be no quick solution.