How events have unfolded since Ian Tomlinson collapsed at the G20 protests in the London on 1 April 2009.
Ian Tomlinson is found unconscious in St Michael’s Alley by a member of the public who shouts for help and calls an ambulance.
Police officers arrive at the scene in Cornhill before paramedics and find he has stopped breathing.
A Metropolitan Police spokesman says police officers came under attack from missiles – thought to be bottles – while they tried to help Mr Tomlinson and moved him to an area outside the Royal Exchange Building where they attempted resuscitation.
A London Ambulance Service crew arrives and tries to resuscitate Mr Tomlinson at the scene and on the way to hospital but he is pronounced dead at hospital.
The Directorate of Professional Standards at both the Metropolitan Police and City of London Police is informed. This case is referred to the Independent Police Complaints Commission (IPCC).
Police formally name the dead man as Ian Tomlinson, 47, a City resident, who was on his way home from work at a newsagent’s. His family say he will be “sadly missed”.
Eyewitnesses describe how protesters went to help Mr Tomlinson after he collapsed.
Fran Legg, 20, a politics student studying at Queen Mary, University of London, says Mr Tomlinson was lying on his back on the pavement but a friend put him in the recovery position while others shouted for medics and called an ambulance.
The ambulance took about 10 minutes to arrive, she says, by which time he had gone very white and was having breathing difficulties.
A second Queen Mary student Elias Stoakes, 25, from Exeter in Devon, questions whether missiles were thrown at officers as they tried to treat Mr Tomlinson.
“One or maybe two plastic bottles were thrown, but it was by people further back in the crowd who did not know what was going on.
“There definitely wasn’t a rain of bottles.
“The idea that protesters did not care is completely false.”
The IPCC announces it is working with City of London police to investigate Mr Tomlinson’s death.
A post-mortem examination finds Mr Tomlinson suffered a heart attack and died of natural causes.
Dozens of protesters return to the scene to demonstrate agains police tactics and question the force’s version of events.
The IPCC says it is managing the investigation by City of London Police into Mr Tomlinson’s death – effectively stepping up their control over the enquiries.
The IPCC say he was pushed back by a police line minutes before his death.
Mr Tomlinson was caught on several CCTV cameras walking up King William Street where he was confronted by uniformed officers.
A short time later, he walked into Royal Exchange Passage where witnesses said he was caught up in a crowd and pushed back by more police officers.
Mr Tomlinson then walked on to Cornhill where he collapsed.
Deborah Glass, of the IPCC, said: “Initially we had accounts from independent witnesses who were on Cornhill, who told us that there had been no contact between the police and Mr Tomlinson when he collapsed.
“However, other witnesses who saw him in the Royal Exchange area have since told us that Mr Tomlinson did have contact with police officers.
“This would have been a few minutes before he collapsed. It is important that we are able to establish as far as possible whether that contact had anything to do with his death.”
Video footage obtained by the Guardian newspaper shows Mr Tomlinson being shoved to the ground by a police officer minutes before his collapse.
He is seen walking with his hands in his pockets with his back to a group of police when one officer, apparently unprovoked, seems to hit Mr Tomlinson with a baton on the leg then lunges at him from behind.
Mr Tomlinson falls heavily to the floor and is seen being helped to his feet by people, thought to be protesters, while police officers are shown looking on.
He is then seen walking unaided past the camera.
The footage was reportedly shot at Royal Exchange Passage by a fund manager from New York who was in London on business.
He told the Guardian he came forward because “it was clear the family were not getting any answers”.
The newspaper said the video would be handed to the IPCC which said it had been made aware of the footage.
A Metropolitan Police spokesman says it would not be appropriate to comment on the video while an IPCC investigation is ongoing.
Photographer Anna Branthwaite, who saw Mr Tomlinson walking towards Cornhill Street, told the Guardian she had seen a riot police officer pushing Mr Tomlinson before the incident captured on video.
“It was a very forceful knocking down from behind. The officer hit him twice with a baton when he was lying on the floor. So it wasn’t just that the officer had pushed him – it became an assault.”
New footage, taken by a Channel 4 News cameraman, shows an officer apparently striking out at Mr Tomlinson with a baton before pushing him to the ground.
The IPCC says it is taking over the inquiry into Ian Tomlinson’s death, which was being run by the City of London police, and reclassifies the enquiry as a criminal investigation.
The watchdog orders a second post-mortem examination in a bid to determine if there was any external factor behind Mr Tomlinson’s fatal heart attack.
It also announces it is to interview the officer seen in video footage after he came forward.
Scotland Yard said no officers had been suspended over the incident. A spokesman said: “A Metropolitan Police Service officer identified himself to his team leader as being potentially involved in the incident shown on the video footage.
“A total of four MPS officers, inclusive of this officer, have now come forward with potentially relevant information in relation to the investigation into the death of Mr Tomlinson.”