Julia Tomlinson described the past four years as “a really hard uphill battle” as her family fought to get to the truth of what happened to her husband Ian.
The 47-year-old was hit with a baton and shoved by Pc Simon Harwood during G20 demonstrations in the City of London and later collapsed and died.
An inquest jury found Mr Tomlinson was unlawfully killed but Pc Harwood was cleared of manslaughter at a trial at Southwark Crown Court last year.
Scotland Yard yesterday apologised to Mr Tomlinson’s relatives as it confirmed that an undisclosed out-of-court settlement has been reached with his family, and the Metropolitan Police paid tribute to the pain his widow and family have “endured with dignity” since his death.
Deputy Assistant Commissioner Maxine de Brunner said: “I take full responsibility for the actions of Simon Harwood on April 1, 2009.
“His actions fell far below the standard we expect from our officers. I accept the finding of the inquest that Mr Tomlinson was unlawfully killed.
“As the jury found, at the time of the strike and push Mr Tomlinson was walking away from the police line. He was complying with police instructions to leave Royal Exchange Buildings. He posed no threat.
“Today, I apologise unreservedly for Simon Harwood’s use of excessive and unlawful force, which caused Mr Tomlinson’s death, and for the suffering and distress caused to his family as a result.”
Mr Tomlinson’s fatal encounter with Mr Harwood was caught on film by a New York hedge fund manager, who passed the footage to the Guardian newspaper.
It showed Mr Tomlinson walking away from a group of police officers and falling to the ground after he was hit and shoved by Mr Harwood.
Mrs Tomlinson said: “Today’s apology and admission by the Metropolitan Police that their officer unlawfully killed Ian marks the end of our campaign and legal case. On April 1, 2009, when we first heard news of Ian’s death we simply wanted to know what had happened.
“We were completely in the dark until a week after his death when we saw the video capturing the violent assault on him by Pc Harwood. The last four years have been a really hard uphill battle. We have had to deal with many obstacles and setbacks.
“After the unlawful killing verdict at the inquest it was unimaginable to us that Pc Harwood could be acquitted of the criminal charge of manslaughter.
“We will never understand that verdict, but at least today’s public admission of unlawful killing by the Metropolitan Police is the final verdict, and it is as close as we are going to get to justice.
“It will always be painful for us that Ian died so violently, but at least he is at rest now, and the force has publicly acknowledged the truth.”
In the immediate aftermath of Mr Tomlinson’s death, officers claimed they had come under a hail of bottles as they tried to help him.
The first post-mortem examination found that he had died from a heart attack, but later it was determined that the cause was internal injuries.