The Privy Council decision to grant Teina Pora an appeal is a significant step which his team will hope will open public purse strings and access to information held by police not yet disclosed.
Pora's team worked on his application to the Privy Council for free after an application for legal aid was turned down last year.
Solicitor-General Michael Heron confirmed that Crown Law would appear in London and said it was expected Pora would make a further application to Attorney-General Christopher Finlayson for legal aid now the Privy Council had decided there were grounds for a new appeal.
The British court has indicated the hearing would be allocated three days and was likely to be in New Zealand's spring.
Pora's lawyer, Jonathan Krebs, has indicated they will also apply for bail for Pora, 38, who in March will have spent 21 years in jail having twice been convicted of the 1992 rape and murder of Susan Burdett.