The United Kingdom’s Serious Fraud Office has said it will charge two former executives of collapsed oil company, Afren Plc, with alleged fraud over payments they received through secret companies relating to over $400m business deals in Nigeria.

Afren, an oil and gas exploration and production company once valued at $2.6bn on the stock market, collapsed into administration in July 2015 after it was unable to service heavy debts.

The SFO, in a statement on its website on Tuesday, said the former Chief Executive Officer, Osman Shahenshah, and former Chief Operating Officer, Shahid Ullah, would appear today (Wednesday) at Westminster Magistrates Court charged with two counts of fraud by abuse of position and two counts of money laundering.

It said they “stand accused over payments they received via secret companies they controlled relating to over $400m of Nigeria business deals.”

“The alleged fraud is claimed to have led to the collapse of the $2.6bn oil giant by their administrators, who in related civil claims, are seeking damages in excess of $500m from the defendants and a Nigerian associate,” the SFO stated

The SFO opened its investigation into Afren in June 2015, according to the statement.

In 2014, Afren sacked its CEO, Shahenshah; COO, Ullah; and two associate directors, Iain Wright and Galib Virani, after an independent review into unauthorised payments found evidence of “gross misconduct”.

An investigation by KPMG and Wilkie Farr & Gallagher, a US law firm, uncovered allegations that payments had been funnelled to them without the knowledge of the rest of the board.

It was alleged that a $45m cut of Afren’s deals in Nigeria was paid into an offshore vehicle for distribution to senior executives.

Afren reported itself to the SFO after details of the alleged secret payments were stated in an independent review by Willkie Farr & Gallagher.

The review began in July 2014 to determine if three legitimate transactions with Afren’s partners in Nigeria, Oriental Energy Resources Limited and AMNI International Petroleum Development Company Limited, in 2012 and 2013 should have been disclosed to the market, according to Reuters.

The review found that Shahenshah and Ullah had agreed with Oriental to receive 15 per cent of the net cash flows that was due to Oriental from the Ebok oil field for five years from 2013 in exchange for $400m in funding by Afren.

Oriental paid $45m in 2013 into a special purpose vehicle owned and controlled by the two top executives, who used the funds to pay bonuses to themselves and selected employees of Afren, the review found.