Court of appeal judges have given the go-ahead for a legal challenge against police practices following fatal shooting of Mark Duggan.

The decision on Friday follows an earlier high court ruling which prevented his mother from seeking judicial review of guidance intended to stop police officers conferring before giving statements.

Lord Justice Maurice Kay, Lord Justice Aikens and Lord Justice Lewison, ruled that there was an arguable case, paving the way for a full hearing at a date to be fixed.

The action brought by Pamela Duggan, whose 29-year-old son died after being shot in Tottenham, north London, in August 2011, relates to a policy adopted by the Association of Chief Police Officers (Acpo).

At the high court in June, Duggan argued that the policy did not include appropriate measures to reduce the risk of officers involved in a fatal shooting conferring with each other before producing accounts.

But at that stage, Lord Justice Laws and Mr Justice Wilkie, presiding, blocked her legal attempt to seek a review, ruling that she did not have an arguable case.

After the appeal, judges gave permission for the case to continue, Marcia Willis Stewart, of law firm representing the Duggan family, said: "This is a case where the use of conferring is of great importance."

She said that before the inquest into Mark Duggan's death, the family brought the judicial review proceedings because of concerns there had been conferring by officers, and following the inquest there was now "clear evidence" that this had happened. "We are therefore pleased that the court has determined there is an arguable claim and that the guidance ought to be looked at," she said.

Kay, vice-president of the court of appeal's civil division, said he had concluded that "notwithstanding difficulties in the case", permission should be granted. He ruled it could not be said that the case was unarguable or had "only a fanciful prospect of success".

There were, the judge said, "arguable grounds for challenging" the Acpo guidance, and directed that the matter be heard at the court of appeal.

Family members and supporters reacted with shock and anger after an inquest jury concluded at the Royal Courts of Justice that police acted lawfully when they shot Mark Duggan.

The inquest jury found Duggan was lawfully killed by a police firearms officer despite being unarmed when he was shot.

His aunt, Carole Duggan, has said the family would fight the verdict itself through the courts.

The fatal shooting sparked riots across the UK in August 2011.