Israel is preventing even a start on rebuilding the swathes of Gaza destroyed during the war by maintaining an embargo on concrete and pipes - arguing that the former could be diverted by Hamas to build bunkers and the latter to launch the home-made rockets that first provoked the war. Thousands of other vital parts needed to repair utilities are also in limbo, and last week the French government said it would withdraw an emergency water treatment unit that was held up at Gaza's borders, in protest at Israel's stance.