Solicitors representing the family of Ian Tomlinson are to review a decision not to charge a police officer over his death.
His widow Julia Tomlinson said she “can't give up on justice” and wants to see Pc Simon Harwood face a jury.
Mr Tomlinson (47) died minutes after he was struck by a baton and pushed to the ground on the fringes of G20 demonstrations in the City on April 1 last year.
Director of Public Prosecutions Keir Starmer revealed yesterday that the Metropolitan Police officer will not be prosecuted.
The Crown Prosecution Service (CPS) revealed conflicting medical evidence stood in the way of any trial for manslaughter.
The decision provoked uproar as the Tomlinson family accused the authorities of a cover-up.
Mrs Tomlinson said: “We want to move on but we can't give up on justice. We don't see how Ian can die moments after being assaulted by the police officer and he isn't made to face a jury.
“It's a scandal. We aren't going to walk away from this.”
A spokesman for Tuckers Solicitors said the decision is “flawed” and open to review, but this may have to wait until an inquest is concluded.
He said: “The family of Ian Tomlinson have instructed us to review yesterday's decision, by the CPS, not to bring charges against Pc Harwood.
“We have considered the decision of the CPS and the detailed reasons given for that decision. Our preliminary view is that the decision is flawed. We are currently assessing the manner and timing of a challenge to the CPS decision.”
Mr Starmer said there was “no realistic prospect” of a conviction after a 15-month inquiry because of “irreconcilable” differences between medical experts.