It was a day that shattered Israel's sense of its own invincibility and military might, undermining the security felt by every one of its citizens.

But it did not seem so extraordinary at the start.

When I saw the early morning "red alerts" on my phone warning of incoming rocket fire from Gaza, we had no idea of the scale of the assault. I messaged my colleagues - some of whom were away for the end of the Jewish holidays - to say that I would head to the office.

Soon I was struggling to absorb the impact of what I was saying on-air, even as the words left my mouth.

The intense missile fire which had me running in and out of the office air raid shelter turned out to be a cover for an unprecedented, complex, long-planned series of attacks.

We saw shocking images of Hamas fighters riding motorbikes through holes cut in Gaza's perimeter fence, paragliding into southern Israel, storming heavily fortified military bases and filming themselves in the gardens of overrun kibbutzim.

Over painful hours, partygoers called into Israeli TV stations describing massacres as they hid from gunmen at the now notorious Nova Music Festival. Terrified residents shared videos of armed Palestinian squads on the streets of Sderot.

It was to prove to be the deadliest day in Israel's 75-year history with people murdered systematically and ruthlessly. From some of the kibbutzim close to Gaza, footage later emerged showing the cold-blooded massacre of entire families. Ultimately, some 1,400 are estimated to have been killed.

The significance of the timing was not lost - as this onslaught came almost exactly 50 years after a surprise attack by Egypt and Syria on the holiest day in the Jewish calendar, Yom Kippur, sparked a major regional war.

The raw pain and shock for ordinary Israelis, still evident now, was on full display when I went to Ashkelon on 8 October.

As Israeli security forces continued to battle heavily armed men literally along the road from us, and rocket sirens continued to blare, at the hospital, parents searched tearfully and collapsed in anguish searching for their missing children.

"Raze Gaza!" one tormented mother shouted.

Early on in the war, there was a thirst for revenge and an urgent desire to restore Israel's deterrence in front of its enemies. However, polls suggest this has since been complicated by growing fears about the impact that intense bombardment and a full-scale ground invasion could have on hostages snatched by Hamas.

Some 240 people are thought to be held: Israelis and foreigners, soldiers and civilians and old and young. Demonstrations and pleas to bring them home are becoming more urgent.

After surviving the nightmare of the Hamas attacks in Nir Oz, the life of Hadas Kalderon is now transformed into desperately campaigning to bring home her two children, Erez, who turned 12 as a hostage in Gaza, Sahar, 16, and Hadas's ex-husband, Ofer. Her mother, Carmela Dan, and her niece, Noya, who were also abducted, have been found dead.

"I don't even have time to grieve [for] my mother and my niece because I have to fight for my children and their father that's still alive," Hadas recently told the BBC. She calls for Israel to stop its military activity until the hostages are safe.

Israel has rejected calls for a ceasefire without the release of all the hostages, and has continued bombarding Gaza from the air.

On Monday, the Hamas-run health ministry in Gaza said that more than 10,000 people have been killed in the Palestinian territory since Israel started bombing it last month.

More than 4,000 of those killed were children, the ministry added.

What compounded the shock of 7 October was the realisation that Israel's military, the strongest in the Middle East, and its renowned intelligence forces had failed to detect the attacks. Many long-time assumptions they had held, together with political leaders, also turned out to be seriously flawed.

After Israel withdrew from Gaza in 2005, and Hamas took full control of the territory in 2007, Israeli authorities had tried to limit the threat it posed along with Islamic Jihad, its smaller ally, also designated as a terrorist group.

It had become common to hear defence experts refer to Israel's strategy in Gaza as "mowing the lawn". The suggestion was that the capabilities of the armed factions could simply be cut back every now and then by Israeli forces - with all that meant in terms of casualties.

There were frequent major conflicts as recently as 2008, 2012, 2014 and 2021.

However, in two previous short rounds of violence in August last year and May this year, which targeted Islamic Jihad, Israel's military took false comfort that Hamas did not join in. The conventional wisdom was that it did not want an escalation.

That assessment proved to be dangerously erroneous. It now seems clear that Hamas was actually biding its time while gaining better weapons, including longer-range rockets and drones, and improving its underground tunnel network.

The idea that Israeli technology had also contained the threat from Hamas - particularly with the costly barrier that was built around Gaza complete with cameras, sensors and a deep concrete base to guard against tunnels - was also shown to be wrong. Last month, thousands of fighters are said to have penetrated the fence in about 30 places.

With war still raging, it is still too soon to give a full list of the mistakes made which led to 7 October.

Israel remains in a state of mourning with the bodies of some of the dead - burnt or mutilated - still unidentified and more soldiers being killed on the battlefield inside Gaza.

However, a wide-ranging, post-war inquiry eventually seems likely. After a turbulent year in Israeli politics, questions may well be asked about the role of the Prime Minister, Benjamin Netanyahu.

Much still depends on how effectively Israel can achieve its new war goals - to dismantle Hamas in Gaza and release the hostages - and deal with the growing threats posed by Iran and its proxies in the region.

One month on from those bloody events in southern Israel, the news remains relentless.