The situation in northern Gaza has been described as 'apocalyptic' by acting UN aid chief Joyce Msuya, as Israel's military offensive against Hamas in the area continues. Using satellite imagery and analysing Israeli evacuation orders, Sky News examines the scale of destruction in northern Gaza since the latest offensive began and the increase in military activity in an area near the Israeli border. It comes as an independent report into the displacement of Palestinians by Human Rights Watch (HRW) suggests that Israel is pursuing a policy of 'ethnic cleansing' in Gaza and its policies and practices are evidence of 'crimes against humanity'.