In a ceremony at Hatzor Air Force Base on Sunday, Prime Minister Benjamin Netanyahu declared the David’s Sling missile defence system operational.

David’s Sling is designed to intercept mid-range missiles, filling the gap between the short-range interceptor Iron Dome and the Arrow 2 and 3 systems, which can deal with high-altitude threats.

Israel is now the first country in the world with a complete, multi-layer missile defence shield covering its entire territory.

However, defence planners have no illusions that it is a perfect system.

Missile interception technology is still in its infancy. David’s Sling has yet to be operationally tested but, since many of its essential components are based on Iron Dome, which achieved a high success rate over the last five years, it is a relatively safe bet. Arrow also scored its first operational “kill” last month when it shot down a large Syrian S200 anti-aircraft missile which, having failed to hit an IDF jet, was on a trajectory towards Israeli territory.

But there are financial question marks. Interceptor missiles are expensive, costing from £60,000 apiece (Iron Dome) to $3m (Arrow 3). Hizbollah, Hamas and other terror groups are estimated to have nearly 200,000 rockets of different ranges, most of them cheap and mass-manufactured.

Meanwhile, Hizbollah and Hamas are stockpiling more accurate missiles.

For these reasons, preemptive attacks on the launch sites will remain an integral part of Israel’s defence doctrine for the foreseeable future.