Nato’s top commander on Thursday called for up to 2,500 more soldiers to be sent to Afghanistan to fight a Taliban-led insurgency that has taken the military alliance by surprise.

General James Jones, Nato’s supreme allied commander, said the alliance’s 26 nations had failed to deliver fully on commitments to staff and equip its force in the country, where a bitter insurgency is raging in the south. He said much of the international strategy for Afghanistan’s reconstruction was on “life support”.