In the far north of the Gaza Strip, so close to southern Israel that the chimneys of a power plant near the city of Ashkelon loom over the horizon, a pick-up truck carrying six camouflage-uniformed men trundles over a bumpy road towards the border.

The militiamen work for the Palestinian territory’s interior ministry, controlled by Hamas, the Islamist group that Israel sees among one of its foremost regional enemies and with which it fought wars in 2008-09 and 2012.

However, their job is not to arm the front lines, but to find and stop renegade militants inside Gaza from firing rockets into southern Israel in violation of the ceasefire declared after the end in November 2012 of Operation Pillar of Defence, in which about 150 Palestinians and six Israelis were killed. […]