Ian Tomlinson's family give their reaction to the decision to charge a G20 police officer with manslaughter Press Association

A police officer will face trial for manslaughter over the death of newspaper seller Ian Tomlinson at the G20 protests.

PC Simon Harwood, 43, a Metropolitan police officer, will face a criminal prosecution for striking Tomlinson with a baton and pushing him to the ground in April 2009.

Tomlinson, 47, had been trying to make his way home from work through demonstrations near the Bank of England when he was pushed from behind. He collapsed and died three minutes later.

Three weeks ago an inquest jury decided Tomlinson was "unlawfully killed".

The director of public prosections, Keir Starmer, had announced in July last year that he did not believe there was sufficient evidence for a prosecution due to complications relating to medical evidence.

However, he said in a statement today that new information had emerged during the inquest and, while difficulties remained, he now believed there was sufficient evidence to bring criminal proceedings.

"Taking the evidence as it now stands, we have concluded that, even with those remaining difficulties, there is now sufficient evidence to provide a realistic prospect of successfully prosecuting PC Simon Harwood for the manslaughter of Mr Tomlinson," he said. "That being the case, it is clearly in the public interest that criminal proceedings be brought.

"Accordingly, a summons charging PC Harwood with the manslaughter of Mr Tomlinson has been obtained from the City of Westminster magistrates court. He will appear before that court on 20 June 2011."

The DPP said the inquest had allowed "a degree of clarity" to emerge and had resolved some complications relating to medical evidence.

The judge presiding over the inquest as assistant deputy coroner had reminded jurors repeatedly that the five-week hearing was not a criminal trial or designed to apportion blame for Tomlinson's death.

Judge Peter Thornton QC said on the opening day of proceedings: "An inquest is very different from cases in other courts. Nobody is on trial. No organisation is on trial. You, as the jury, will not decide any question of criminal or civil liability. That is why you are a jury of 11, for example, a historically different number to a jury in criminal cases."

Jurors were told there were two possible explanations for Tomlinson's death. The first pathologist to examine his body, Dr Freddy Patel, concluded that he died of coronary artery disease.

However, three other forensic pathologists disagreed, concluding that he died of internal bleeding.

On 3 May, the inquest jury returned a verdict of "unlawful killing", stating that Tomlinson died as a result of internal bleeding in the abdomen. The Crown Prosecution Service immediately said it would review its earlier decision not to bring criminal proceedings against Harwood.

In a detailed statement setting out the reversal of his earlier decision, Starmer said: "The difficulty facing any prosecution in relation to the death of Mr Tomlinson lies in the conflicting medical evidence about the cause of death. That difficulty remains.

"A criminal trial is different to an inquest and it is my duty to ensure that a prosecution is only brought where there is evidence available to the prosecution that provides a realistic prospect of a jury being able to satisfy themselves beyond reasonable doubt that an offence has been committed. For that reason very careful consideration is required where there is conflicting medical evidence.

"However, matters have moved on in two ways since the original decision was taken in this case. First, new medical evidence was presented at the inquest. Second, the various accounts and opinions given by the medical experts, including Dr Patel, were tested in extensive questioning at the inquest; this has changed the basis upon which the case falls to be considered."

The DPP indicated that the inquest process had itself been important. "But for the inquest, the significant conflicts in the evidence that had previously existed could not have been addressed; and the inquest process, which is less confined than a criminal trial, has allowed a degree of clarity to emerge."

He added: "We have considered the new evidence adduced at the inquest and the final positions adopted by the medical experts very carefully indeed.

"Having done so, we are satisfied that the position in relation to the medical evidence about the cause of death has clearly changed. The difficulties that would now confront any prosecution have changed in nature and scale from last year when a decision was taken not to prosecute, although it is clear that real difficulties remain."

Starmer reminded the media that care should be taken to avoid prejudicing criminal proceedings against Harwood. "He has the right to a fair trial. It is extremely important that nothing should be reported which could prejudice his trial."

Ian Tomlinson's son Paul King said in a statement on behalf of the family: "We welcome today's decision to bring a charge of manslaughter against the officer. We believe this is the right decision. What we have always wanted is to achieve justice for Ian and to show that police officers are not above the law."

Responding to the CPS decision, Metropolitan police commissioner Sir Paul Stephenson said: "This is clearly a very, very serious matter for all concerned.

"I have got to be very, very concerned at an inquest verdict that returns a verdict of unlawful killing involving, as the inquest did, one of my police officers. My sympathies continue to be with the Tomlinson family."