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Israel's renowned Iron Dome was overwhelmed by the sheer volume of Hamas rockets launched from Gaza, which were on a scale no defence system in the world could have dealt with, military analysts have told The National.
An estimated 3,000 rockets were fired, leaving hundreds dead and thousands injured.
Combined with a lack of intelligence and shortage of staff, the inability of the Iron Dome to deal with Hamas's attack strategy left Israel vulnerable.
Although regarded as the world’s leading defensive system, with only 20 rockets in four launchers per battery it would have rapidly exhausted its stockpile during Saturday's strike, with reloading taking some time.
The Iron Dome, which has an estimated 11 batteries, is also designed to prioritise the most threatening missiles – such as ICBM or cruise – over smaller rockets or the microlights used by Hamas.
“This very well co-ordinated attack meant that rather than 10 or 20 rockets being launched from one place into Israeli airspace, this was happening from multiple angles, which makes air defence really hard,” said Sam Cranny-Evans of the Royal United Services Institute think tank.
That it was a Saturday amid the Jewish celebration of Simchat Torah meant even fewer troops were on duty, leading to a slower response time, he added.
“It was definitively a surprise but it was also overwhelming, achieving quite a shock effect,” said Mr Cranny-Evans.
“The sheer scale of what was happening overwhelmed their decision-making ability and their ability to understand it.”
Brig Ben Barry, of the International Institute of Strategic Studies think tank, said that for the Iron Dome there was “a finite limit to its capacities to knock stuff out of the sky”.
“With thousands of rockets in the air in a very short period of time there is not a single air defence system in the world that's going to be able to cope with that," he said.
By comparison, Russia’s biggest attacks on Ukraine with cruise missiles, rockets and drones amount to about 100 projectiles enabling the defenders to shoot down the vast majority.
Brig Barry, an urban warfare specialist, suggested the intricate Israeli eavesdropping devices and sensors along its 65km barrier may not have failed but were instead also overwhelmed.
“It may be that the Israelis were not present on the fence or in their fortified camps in sufficient strength, and their quick reaction forces couldn't get there quickly enough,” he said.
“The fence is a linear defence and you can have all the sensors and surveillance technology you want but if you can't react to an attempted breach quickly enough, it is redundant.”
At the same time as its rocket attack, Hamas launched a land, air and sea invasion, which temporarily proved too much for Israeli defences.
“Hamas performed exceptionally well in all aspects of their planning, intelligence gathering and execution,” said Michael Stevens, a leading British authority on the Middle East.
“It was a well masterminded but extremely brutal attack.”
Israel’s autonomous heavy-machinegun towers, designed to open fire on border incursions automatically, were also targeted by Hamas drones dropping grenades in a similar tactic used by Ukraine on Russian tanks.
A source connected to Israeli intelligence told The National that Hamas had also allegedly “deliberately created tension” in the West Bank town of Huwara to draw troops from guarding the Gaza Strip.
“This resulted in some troops being moved from what was perceived as a quiet front that meant that of three battalions that normally surround Gaza, only one was present and the other two were in Huwara,” the source said.
Mr Stevens said that violence in the occupied West Bank forced Israel to “divert resources of several battalions away from Gaza that should have been in Gaza”.
He also suggested the catastrophic intelligence failure was a result of Israel’s current political infighting that had affected its security agencies.
“There has been increasing competition inside security ministries for roles and access to certain positions that are now been dominated by political players,” he said.
“Israeli [intelligence] has dropped a little bit qualitatively as a result of its domestic political failings.”
Meanwhile, Danny Yatom, the former head of Mossad, the national intelligence agency of Israel, said "everything" went wrong in dealing with Hamas’s attack.
Speaking on BBC Radio 4’s Today programme, Mr Yatom said not enough forces were deployed due to a failure of intelligence, which came on top of years of policies that had allowed Hamas to galvanise.
“Nobody had any clue that on 6.30am on Saturday, 50 years and one day after the total surprise that we were caught under in the Yom Kippur War, we would witness it again,” he said.