A police constable caught on camera striking Ian Tomlinson and pushing him to the ground has been suspended and questioned on suspicion of manslaughter.

The newspaper seller's death during G20 Summit protests in London has thrown the policing of mass demonstrations under the spotlight.

Here is a timeline of how events have unfolded since April 1:

:: April 1

Mr Tomlinson is confronted by uniformed police officers as he walks up King William Street, a short distance from the Bank of England, at about 7.30pm.

He is trying to make his way home across the City to watch football, but is blocked by cordons surrounding thousands of protesters still in the area.

A short time later he walked into Royal Exchange Passage where witnesses say he was caught up in a crowd and pushed back by more police officers.

He then collapses in Cornhill where he is attended to by police medics and shielded from onlookers by a ring of officers.

:: April 2

A Metropolitan Police spokesman says officers treating Mr Tomlinson had bottles thrown at them by protesters. The Independent Police Complaints Commission (IPCC) is alerted to oversee a City of London Police inquiry.

:: April 4

City of London Police say a post mortem examination found Mr Tomlinson suffered a fatal heart attack and died of "natural causes".

:: April 7

Dramatic amateur footage emerges of Mr Tomlinson being shoved to the ground from behind by a police officer. It is passed to the Guardian by a New York fund manager.

He tells the paper: "The primary reason for me coming forward is that it was clear the family were not getting any answers."

Mr Tomlinson is seen walking with his back to a group of police when one officer lunges at him from behind. He then falls heavily to the floor.

Other witnesses come forward to claim Mr Tomlinson was also hit by police in the minutes before the footage was filmed. Among the witnesses is freelance photographer Anna Branthwaite.

Mr Tomlinson's stepson Paul King says: "Whether that was a cause to his death we are not to know. We want answers: why?"

:: April 8

The IPCC takes over the inquiry. It orders a second post-mortem examination in a bid to determine if there was any external factor behind Mr Tomlinson's fatal heart attack.

The watchdog also announces it will interview the officer seen in video footage after he came forward. Three other officers also come forward with information.

:: April 9

The policeman caught on camera hitting Mr Tomlinson is suspended. He is a constable from the territorial support group, based in Lambeth, south London.

Scotland Yard denies claims it tried to mislead the public over the death of Mr Tomlinson.

:: April 10

IPCC chairman Nick Hardwick says the inquiry will be "independent, fast and effective".

:: April 11

Mr Tomlinson's family say they are "hopeful" action will be taken against any police officer whose wrongdoing contributed to his death.

Speaking during a memorial march across London, Mr King says it was painful to watch footage of the "violent assault" on his stepfather.

:: April 14

A second officer, a police sergeant from the territorial support group, is suspended after footage emerges on YouTube of him striking Nicky Fisher, 35, at a vigil for Mr Tomlinson on April 2.

:: April 15

Commissioner Sir Paul Stephenson calls in Government inspectors to examine his force's tactics when faced with mass protests.

Her Majesty's Chief Inspector of Constabulary Denis O'Connor will lead the review of strategies such as "kettling", the confinement of people in one place for extended periods.

Sir Paul says police footage of clashes will be reviewed to see if any other incidents need to be looked at and highlighted how all uniformed officers must wear shoulder identification numbers.

The IPCC announces it will investigate the second incident of alleged police brutality.

:: April 16

A total of 145 people have complained to the IPCC following angry clashes between police and protesters during the G20 summit, the watchdog says.

:: April 17

The police officer suspended following the death of Mr Tomlinson has been questioned on suspicion of manslaughter, the IPCC says.

He was questioned after a second post mortem examination finds Mr Tomlinson died from an "abdominal haemorrhage" and not a heart attack.

Mr King says: "First we were told that there had been no contact with the police, then we were told that he died of a heart attack.

"Now we know that he was violently assaulted by a police officer and died from internal bleeding. As time goes on, we hope that the full truth about how Ian died will be made known."