The Group of Eight richest nations will come under strong pressure at their annual summit in Hokkaido next week to boost food aid sharply, after the Asian Development Bank added its voice to those warning that rising prices pose a grave threat to the world’s poor.

Haruhiko Kuroda, ADB president, said soaring prices for cereals, rice and other staples risked malnutrition for 1bn Asians, who spend at least 60 per cent of their income on food.