The jailed former governor of Delta State, James Ibori, lost a legal appeal on Thursday against a 13-year prison sentence for embezzling 50 million pounds ($78 million) in one of Britain's biggest money-laundering cases.

Ibori, who ran Delta State for 8 years, was trying to get his sentence reduced. His lawyers argued that the original judge had indicated the term would be shorter.

Judge Antony Edwards-Stuart rejected that argument at the appeal hearing and also said that money laundering should attract close to the maximum 14-year sentence.

Ibori pleaded guilty to 10 charges of fraud and money-laundering in February 2012 and is the most prominent Nigerian politician to be successfully prosecuted for corruption, in one of the most graft-ridden countries in the world, according to monitoring group Transparency International.

The Ibori case was heard in London after prosecutors argued that, although much of the activity in question took place in Nigeria, some money did pass through Britain and British banks.

During his trial last year, a London court heard the stolen fortune was used to buy six foreign properties and a fleet of cars, although the judge said the total amount stolen may in fact be "in excess of 200 million pounds".

The biggest single fraud involved misappropriating $37 million in fees when Ibori's Delta State sold its stake in the Nigerian mobile telecoms company V Mobile.

The Ibori case was heralded as a major success for London's police, with Britain long seen as a destination of choice for corrupt Nigerian politicians to spend their ill-gotten gains.

Ibori, who was elected governor of Delta in 1999 during Nigeria's transition from military to civil rule, could still play a prominent role in Nigerian public life on his release.

Eligible for parole halfway through his jail term, he is likely to be out of prison in 3-1/2 years, having served a year since the trial, a year beforehand awaiting trial in London and a year in Dubai from where he was extradited to Britain.