Footage of an incident at Manchester Airport between police officers and members of the public went viral on social media in July.
A timeline below sets out what happened:
July 23:
According to Greater Manchester Police (GMP), an altercation takes place between passengers from a Qatar Airways flight which arrives at Manchester Airport at 7.20pm.
A second incident, which police describe as a “violent altercation involving members of the public”, happens in the Starbucks of Terminal Two just after 8.20pm.
A third incident happens in the car park pay point area shortly before 8.30pm.
Brothers Mohammed Fahir Amaaz, 20, and Muhammed Amaad, 25 and their mother Shameem Akhtar, 56, from Rochdale, are allegedly assaulted.
Police say three of their officers receive head injuries, including a broken nose.
Four men are arrested at the scene for affray and assault on emergency service workers.
July 24:
A police officer is removed from operational duties after footage of the incident, appearing to show a man being kicked and having his head stamped on as he lies on the floor, is shared online.
Police make a voluntary referral of their response to the Independent Office for Police Conduct (IOPC).
That night, an estimated 200 people gather outside Rochdale police station to protest in response. GMP say the protest concludes “without incident”
July 25:
A GMP officer is suspended from all duties. The IOPC confirms it is independently investigating the level of force used.
Mayor of Greater Manchester Andy Burnham says he has seen full footage of the incident, which shows a “fast-moving and complicated” situation with “issues for both sides”.
Protests in Manchester city centre that evening involve blocked roads and tram lines while videos online appear to show a handful of demonstrators with their faces covered, throwing eggs at Rochdale police station.
Rochdale MP Paul Waugh says he has spoken to the family involved and they want to appeal for calm.
July 26:
The IOPC announces that a police constable is under criminal investigation for assault and has been told he is being investigated for potential gross misconduct for a number of alleged breaches of professional standards, including his use of force.
Former Rochdale MP George Galloway visits the town and says he plans to meet the family involved.
July 27:
New footage, appearing to show events in the moments before the video which has already been shared, becomes public.
The Manchester Evening News publishes the video, which appears to show men throwing punches at officers.
Two female officers appear to be struck, with one ending up on the ground.
August 1:
Solicitor for the family, Aamer Anwar, says he has spoken with the IOPC about lodging a formal complaint against officers and says the family wants to understand on what legal basis Mr Burnham was shown the complete CCTV.
August 6:
The family and their lawyer hold a press conference in which they outline their version of events.
August 8:
The IOPC reveals a second officer is under criminal investigation for assault, relating to an incident shortly afterwards when two other men were arrested.
The watchdog’s acting regional director Catherine Bates says its investigation is ongoing in parallel with a GMP investigation into whether criminal offences were committed by members of the public.
August 15:
GMP says a “comprehensive file of evidence” has been submitted to the Crown Prosecution Service (CPS) for advice as part of an investigation into a series of alleged criminal offences.
September 5:
The family meet with the IOPC to discuss progress on its investigation.
September 6:
A spokesman for the police watchdog says it will investigate whether someone employed by the force shared footage.
October 7:
MPs from Reform UK write to Home Secretary Yvette Cooper, pledging to launch a private prosecution against those involved if charges are not brought by the CPS.
November 18:
The CPS says it is still “considering material” and working with police and the IOPC while inquiries continue.
Reform UK leader Nigel Farage says the party will make a legal application.
December 20:
It is announced that Mohammed Fahir Amaaz, 20, has been charged with two offences of causing actual bodily harm, one charge of assaulting an emergency worker and one charge of common assault, and Muhammed Amaad, 25, has been charged with one count of causing actual bodily harm.
No police officers will be charged, the CPS says.
