Ian Tomlinson's widow Julia 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.
"It was, and still is a shocking video. We knew that Ian had been unlawfully killed by the officer as soon as we saw the video, but we had to first go through the long legal process of taking apart untruthful accounts given by PC Harwood and other police officers. We should not have had to do this.
"The last four years have been a really hard uphill battle. We have had to deal with many obstacles and set backs. 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. We hope that lessons have been learned and that other families will be spared the tragedy and ordeal that we have had to face.
We loved Ian and will always keep his memory alive by talking about him and sharing our memories with each other as we finally start looking to the future again."
The widow of Ian Tomlinson said that an apology and settlement from Scotland Yard is "as close as we are going to get to justice".
In a statement, the Metropolitan Police says all the litigation between the Commissioner and the Tomlinson family has been resolved.