A Zambian high court judge on Friday granted ex-president Rupiah Banda the right to challenge parliament's decision to remove his immunity, the first victory in a politically-tinged legal battle.
Parliament on 15 March stripped Banda of immunity so that he could be prosecuted for alleged offences committed during his three-year tenure as head of state.
But Judge Annie Sitali ruled that lawmakers erred in voting on a matter before courts could consider an application to block their debate.
"The applicant has a fit case which should go for a substantive judicial review," Judge Annie Sitali ruled following the challenge by Banda.
Banda faces a slew of graft charges, in what allies say is an attempt by his successor as president, Michael Sata, to neutralise political opposition.
Banda, president from 2008 to 2011, is accused of benefiting from a Nigerian crude oil contract while in office.
He has denied the charges and launched court action to win back immunity from prosecution.
The judge noted that her ruling would not stop criminal charges from going ahead.
"Civil proceedings cannot arrest criminal proceedings," Sitali said.
Banda was not in court Friday.
Only his aide Mikatazo Wakumelo and eldest son Andrew appeared.