A British prosecutor launched a fresh attempt on Thursday to confiscate tens of millions of pounds stolen from an oil-producing state in Nigeria by its former governor, who was convicted of laundering his loot in Britain.

James Ibori, who was governor of Delta State from 1999 to 2007, pleaded guilty at London's Southwark Crown Court in 2012 to 10 counts of fraud and money-laundering. He received a 13-year jail sentence.

The case was a rare example of a prominent Nigerian politician being punished for his part in the endemic corruption that has blighted Africa's most populous country for decades.