A logo is seen under a canopy of trees at a Shell petrol station in central London
Royal Dutch Shell and Eni could "fall foul of anti-corruption legislation" in Britain over a $1.1 billion Nigerian offshore oil block the companies bought last year, campaign group Global Witness said on Monday.
Block OPL 245, which holds an estimated 9 billion barrels of oil, had been owned by former Nigerian oil minister Dan Etete's company Malabu Oil and Gas. It was later awarded to Shell, starting a decade-long legal dispute that ended last year, reports Reuters.
Shell and Eni have repeatedly said they paid the Nigerian government last year for the oil block, which Eni operates, and that they never dealt with Malabu.
Etete originally acquired the asset in a deal conducted while he was oil minister for military ruler Sani Abacha in the 1990s. He was convicted for money laundering in France in 2007.
Local newspapers quoted Nigeria's Attorney General Mohammed Adoke in May as saying that Shell and Italian company Eni agreed to pay Malabu the money for the block, with the government as an intermediary.
"If ... Shell and ENI knew that the ultimate destination of the funds would be Malabu and Etete, then this transaction might well fall foul of anti-bribery legislation in the U.K.," Global Witness, which campaigns against natural resource-related conflict, corruption and associated abuse, said in a report.
"A substantial monetary 'reward' ended up being paid to a company controlled by an individual who had arguably abused his public position," the report added.
Global Witness said a consultant central to the Malabu deal submitted a sworn affidavit to a U.S. court, which described direct negotiations between Shell, Eni and Malabu.
The Italian oil company said in a statement on Monday: "Eni or any of its affiliates have not entered into a Memorandum of Understanding with Malabu."
"The payments ... have been made to the Federal Government. Such payments were made in a transparent manner."
Shell did not immediately respond to a request for comment but it has said before that the deal was done transparently with the Nigerian government and not with Malabu.
Nigeria is Africa's largest oil producer and holds the world's ninth-largest natural gas reserves. Its energy industry is rife with corruption, highlighted in several government-commissioned audits and reports.