The report by the London Assembly, the city's elected parliament, said the most striking failure was the lack of planning to care for thousands of people who survived or were traumatised by the July 7 attacks.
A total of 56 people were killed, including the four suicide bombers, and many more hundreds injured when the bombs exploded on three underground trains and a bus during the morning rush hour.
"They focused on incidents but not individuals, and processes rather than people," said Richard Barnes, who chaired the elected assembly's July 7 review committee.
The report said most were allowed simply to walk away from the blast sites without anyone in authority taking their details.
As a result, the 700-page report said, hundreds and possibly thousands of survivors who may have suffered psychological problems had been left without any support, counselling or advice since the explosions. This was "completely unacceptable," it added.
The latest findings are in the third report on the deadliest terror attacks to occur on British soil, after two previous ones concluded that the security services had lacked resources to prevent the bombings.
Communications breakdown
The report said that the inability to talk by radio while underground was "unacceptable," and criticised the reliance on mobile telephone networks which predictably became congested during the crisis.
As a result of the communications breakdown, some emergency services staff at the blast sites could not communicate with each other or in some cases even with their control rooms.
The report said radios used by most blue-light emergency services still did not work underground, despite recommendations made 18 years ago in the wake of a fire in which 31 people died in an underground station at King's Cross.
"Communications within and between the emergency services did not stand up on July 7," it added.
The chaotic aftermath of the bombings had also exposed London Ambulance Service's "lack of capacity" to deliver equipment and medical supplies to the scene of a major incident at multiple sites, the report went on.
"There was a lack of basic equipment, such as stretchers and triage cards, and a lack of essential supplies such as fluids."
The Evening Standard newspaper noted that it took 23 minutes for the first ambulance to arrive at the Aldgate Underground train station, and that there were no fire engines at Russell Square station an hour after the blast there.
The report by the review committee of the assembly, the 25-member elected body which reports to Mr Livingstone, recommended an overhaul of emergency plans, systems and processes and scheduled a follow-up review for November.