There were several emotional comparisons between Aleppo and Dresden in yesterday's papers. Of course, if Churchill and Sir Arthur Harris had ordered the 'terror' bombing of German cities after 1949 they could have been prosecuted as war criminals, and likewise had the Germans shot 330 Italian hostages at the Adeantine caves after 1949, this, too would have been a war crime. As it is, both actions were within the terms of the Geneva convention when they happened, and thus free of criminal blame.
The use of White Phosphorus, WP or Willie Peter in US vernacular, was defended by US General Peter Pace in 2005; "(WP is) a legitimate tool of the military, used to illuminate targets and create smokescreens. It is not a chemical weapon. It is an incendiary". WP has been used by the US most recently in Iraq and Afghanistan, and also by the KSA, Israel and by the Ukrainians. Now, it is alleged, it is being used by Assad against ISIS and the insurgent rebels in Aleppo.
Given our biggest ally's reliance on White Phosphorus munitions, it is perhaps a little disingenuous of the UK ambassador to to the UN to condemn its use in the Syrian civil war. No doubt the FCO instructed him to bluster and whine and the poor man was just doing as instructed.
As ever, the military of both sides are just doing what the military of the world always has to do. Those really responsible for the prolonged death and suffering are the heartless Saudi, Turkish, US and European powers who fund and arm the continued killing with their support of ISIS, Al Queda and other Sunni insurgents against the Syrian government.