The message from the Taliban

Yesterday, Nato commanders' fears appeared to be born out after a roadside bomb killed five US soldiers in the Maiwand district of southern Afghanistan.

As the drawdown of Nato troops enters its final 18 months – with British forces due to pull out of the country by the end of next year – the summer campaigning season has now begun and it seems likely there will be a spate of similar attacks in the months ahead.

By any military standards, blowing up the Mastiff used by The Royal Highland Fusiliers 2nd Battalion Royal Regiment of Scotland (2 Scots) was a massive publicity coup for the Taliban.

Although no vehicle or weapons system is ever completely infallible, the introduction of the six-wheeled 15-tonne Mastiff had built up confidence among British soldiers for its reliability and strength while out on patrol.

Other Mastiff armoured vehicles have survived similar attacks but by destroying one, the insurgents provided evidence they have the explosives and the technology to produce roadside bombs of sufficient strength to knock them off the road and kill those on board.

The attack also means the doubt factor remains for soldiers using these vehicles and gives notice that a dangerous war is still being waged. That is an important point for the insurgents, as the security situation is currently in a critical phase in Helmand province. After several setbacks, including a spate of killings by Afghan security personnel, Nato forces are in the process of handing over primacy in operations to their opposite numbers in the Afghan army and police.

That is one reason for the presence of 2 Scots, who are engaged in the mentoring and training of Afghan security personnel. It is a painstaking business, which carries obvious risks but it is bearing fruit.

In the capital Kabul, Afghan police are in complete control but in outlying areas such as Helmand, progress has been slower due to the tribal nature of local society, the deep-lying suspicions of Nato troops and a general dislike of Western influence.

For local Taliban warlords, the Western presence is an affront to their own influence and that helps to explain why fighting is continuing and intensifying.

In a counter-insurgency war of this kind, perception is often as important as reality and in advance of next year's Nato withdrawal, the Taliban are keen to be seen to be keeping up the fight and not taking any backward step. If they can discomfort Nato forces, it becomes easier to persuade the local population they are winning the war. Such an argument will be an important factor in the elections, which will follow the final removal of Western forces from Afghanistan.

It is difficult to forecast how it will end, as everything depends on the ability of the homegrown security forces. If they can be in position and have become a trustworthy and professional organisation capable of operating in a dispassionate and legal way, they will gain the trust of the local population and so doing will be a success story.

Meanwhile, military officials say "lessons will be learned" after last week's attack. Helmand is less risky in that soldiers are not walking around every day. However, this is a place which has seen 35 years of warfare – there are explosives left over from the Soviet occupation.

Meanwhile, the Taliban watch and wait. It is not in their interests to see the emergence of efficient security forces for the simple reason that if they lose the population they will have lost the war. That helps to explain the their determination to keep the pressure on Nato forces, to attack them and to kill, not just out of military necessity but because it shows people they are still a power.

If Nato forces leave the country after suffering a succession of military losses, however minor, it becomes easier for the warlords to claim victory over a more powerful enemy. Every Nato casualty, every upturned armoured vehicle and every awkward headline in the Western media only adds to that perception.