On 22 May 2017, suicide bomber Salman Abedi detonated a bomb in the foyer of Manchester Arena after an Ariana Grande concert.
In total, 22 people died and hundreds more were injured - including many children and teenagers.
A Timeline of Events
6pm: Doors open
Some 14,200 fans start to arrive at Manchester Arena ready for the concert. A number of the tickets were Christmas or birthday presents.
8:30pm: Abedi arrives at Victoria Station
CCTV footage shows Salman Abedi in and around the Victoria Metrolink carrying the rucksack on his back. From there, he goes to the public toilets where he remains in a cubicle for 10 minutes. He then takes the lift to the Manchester Arena concourse.
8:49pm: Security sweep misses Abedi
Abedi leaves the toilets just before British Transport Police PCSO's conduct a security sweep, missing him by 59 seconds.
8:51pm: Abedi enters the City Room
After leaving the toilet, Abedi takes the lift to the footbridge that leads to the concourse and goes to the City Room - the foyer for the Arena. He stays there out of sight for 19 minutes before re-tracing his steps to the Metrolink platform where he sits for a further 16 minutes.
9:29pm: Abedi returns to the City Room
He will remain here until people begin to stream out of the concert.
9:36pm: Police return from break
A BTP officer and PCSO return to patrol after going to get kebabs. The break lasted just over two hours. They missed Abedi walking from Victoria towards the City Room by minutes.
10:15pm: Member of the public reports Abedi to security
Minutes later, the security staff member alerted another colleague who attempts to radio control, but says the line is busy. This is the final image released before the 22-year-old carried out the terror attack.
10:31pm: Bomb detonated
Salman Abedi detonates his rucksack bomb, murdering 22 bystanders and injuring many others.
The Emergency Response
10:33pm: First call to Greater Manchester Police
52 seconds later, a member of the public - Ronald Blake - dials 999.
British Transport Police declare a major incident was declared after reporting 60 plus casualties.
10.34pm: North West Fire Control is first notified of the bombing and mass casualties. They also, wrongly, receive reports of an 'active shooter'
10:42pm: First paramedic arrives at Victoria Station
The paramedic is later joined by two others - they are the only three paramedics to enter the City Room all night.
10:43: Armed police arrive at the scene within 10 minutes
10.47pm: The force duty officer is heard declaring Operation Plato within police HQ - the code name for a marauding terrorist attack
Operation Plato should have triggered a co-ordinated emergency response. But the police don't tell fire or ambulance crews.
10:49pm: There are 12 ambulances at the scene
Three paramedics are now with the injured, while the rest set up a treatment area on the train station concourse.
Continued confusion over whether there is an active shooter or a secondary device means other paramedics are held back.
Fearing it isn't safe the fire service also decide to stay away - leaving many crews feeling frustrated.
12:37am: Two hours six minutes after the blast the first fire engine arrives at the arena
Three engines arrive, after they had been told to wait at Philips Park Fire Station - around three miles from the arena.