Israel-Hamas war: what has happened and what has caused the conflict?

Offensive launched from Gaza represents large failure of Israeli intelligence and is likely to have long-lasting repercussions

• Live updates: Israel and Hamas at war
• What we know so far: day two

Shocked Israelis woke on the last day of the Jewish high holidays to the wail of sirens as Hamas and Islamic Jihad fired thousands of rockets from Gaza and armed militants broke down the hi-tech barriers surrounding the strip to enter Israel, shooting and taking hostages. Militants in boats also tried to enter Israel by sea.