This year its sales hit 8.3m, which includes total booking revenue.

Last year a review of its accounting policies found numerous errors in how the agency booked revenues and accounted for costs.

No small matter for any operator in an area beset by bickering about which government books revenues from oil and gas sales.

The company reported an operating profit of €344m for the period after booking revenues of €1.9bn.

The firm, which relies heavily on the fees earned on deals, dismissed the drop in net income as a technicality linked to when it booked revenue.