Niger Delta is one of Nigeria's potentially richest states, but remains underdeveloped due to corruption [EPA]

A former Nigerian governor facing allegations of funnelling at least $200m in stolen state funds to British banks has been extradited from Dubai to London, Nigeria's anti-corruption body says.

James Ibori, who was governor of the oil-rich Delta state, was extradited hours before tens of millions of Nigerians vote in Saturday's presidential election.

According to diplomatic cables published by WikiLeaks, the whistle-blowing website, Ibori funnelled $292m to unnamed British banks.

Femi Babafemi, the spokesman for Nigeria's Economic and Financial Crimes Commission, said Ibori fled to Dubai after a warrant for his arrest was issued in Nigeria.

He called Ibori's arrest "a warning to others who do everything to slow down the wheel of criminal prosecution in Nigeria".

Ibori was detained in Dubai in May on an Interpol warrant, but it is unclear how long he remained in police detention there. Dubai's highest court ordered Ibori's UK extradition in December.

Scotland Yard confirmed on Friday that Ibori had been flown from Dubai to Heathrow with a police escort and was in custody in west London, 10 months after one of his aides was convicted of money laundering charges in a British court.

Nigerian authorities said the process was delayed after Ibori claimed he was a victim of political persecution.

Ibori was a major contributor to the election campaign of Umaru Yaradua, the late president whose successor, Goodluck Jonathan, is now running for the office himself.

Nigeria's anti-graft investigators had arrested Ibori in 2007, but the cases against him foundered as his political power grew.

After contributing his wealth to Yaradua's election in 2007, Ibori served as a trusted confidant to the president who died while in office last May.

Diplomatic cables released in February by WikiLeaks website showed that the Yar'Adua government had sought to block an investigation into Ibori.

Nigeria's former attorney general, Michael Aondoakaa, demanded that evidence against Ibori be returned from the UK to Nigeria as it had come by "inappropriate channels", said the cable, one of many mentioning the politician dogged by corruption allegations.

Jonathan dismissed Aondoakaa while he was still acting president during Yaradua's illness.