Mark Duggan's mother has been given limited permission to launch a judicial review following the inquest into his death.
The High Court has allowed Pamela Duggan to challenge the direction given to the jury by Coroner Keith Cutler, who presided over the inquest into the death of her son.
In January, jurors agreed by a majority verdict of eight to two that Mr Duggan was lawfully killed when he shot dead by an armed police officer referred to as V53 in Ferry Lane, Tottenham, in August 2011.
The conclusion was reached despite the jury agreeing that the 29-year-old was unarmed when the officer opened fire.
Mr Duggan’s death sparked riots in Tottenham which later spread across the country.
Permission for judicial review was granted because the direction given by the coroner was “arguably inadequate”.
It was argued that he failed to make clear that jurors must conclude on the balance of probabilities that: “V53 did not honestly, even if mistakenly, believe that Mark Duggan held a gun in his hand immediately before he was shot.
“If V53 had that honest belief and it was mistaken, the mistake must have been a reasonable one for him to have made.”
Mrs Duggan claims the coroner’s direction did not address either of these questions and if they had been then a conclusion of “lawful killing” cannot stand.
No date has as yet been set for when the issue will be heard in court.