The conviction of Ziad Akle, a former Unaoil executive jailed last year for bribery, has been quashed and the UK Serious Fraud Office (SFO) was accused of a "serious failure" in a damning judgment by London's Court of Appeal.
Senior judges refused an SFO request for a retrial for the 46-year-old, who was jailed in 2020 for five years for conspiracy to bribe an Iraqi official to secure an oil deal after the fall of Saddam Hussein in 2003. Akle's lawyer confirmed that he would be released on Friday.
The ruling, made public on Friday, raises questions about the convictions of Akle's co-defendants and could rekindle a debate about the future of the SFO - a novel enforcement agency that combines investigatory and prosecutorial powers, one lawyer said.
The Court of Appeal said the SFO had refused to provide the defense with documents necessary to fight its case, which is required by law, undermining Akle's right to a fair trial.
"That failure was particularly regrettable given that some of the documents had a clear potential to embarrass the SFO in their prosecution of this case," senior judges said in their judgment.
But the judges did not suggest any individual SFO officials "had deliberately sought to cover anything up".
The SFO, which in July promised a review of its handling of the case, said it was assessing the judgment.
The five-year SFO investigation into Monaco-based energy consultancy Unaoil - founded and run by the prominent British-Iranian Ahsani family to help major Western companies secure energy projects in the Middle East, Central Asia and Africa over nearly two decades - has proved thorny.
The SFO secured four convictions. Akle, Unaoil's former Iraq territory manager, former colleague Stephen Whiteley and Paul Bond, a former sales manager for energy services company SBM Offshore, were convicted by jury. Basil Al Jarah, Unaoil's former partner in Iraq, pleaded guilty in 2019.
Akle's appeal turned on the role played by David Tinsley, a former drug enforcement agent who founded Miami-based investigative firm 5 Stones Intelligence and worked for the Ahsanis - once the SFO's prime suspects - who have since pleaded guilty to bribery in the United States.
Akle's lawyers alleged that senior SFO officers - including director Lisa Osofsky - had breached their duties by engaging with Tinsley, who promised to try and secure guilty pleas from Akle and Al Jarah, although he did not represent them.
The Court of Appeal said that notes of a 2019 telephone conversation with Tinsley could be viewed as the SFO recognizing this - and accepting those advantages.
"This judgment sends a clear message – the SFO can no longer engage in backroom deals," said Jo Dimmock, a Paul Hastings partner who represented Akle.
(Reporting by Kirstin Ridley Editing by David Goodman and Susan Fenton)