LONDON (Reuters) - Three former executives of the one-time UK division of German logistics and freight company Bertling have been convicted of bribery alongside a former logistics official after a British investigation into North Sea oil exploration contracts.

The Serious Fraud Office (SFO) said on Tuesday the latest trial brought to nine the total number of convictions landed - which include one for FH Bertling Ltd itself - in a four-year investigation into corrupt schemes in the North Sea and Angola.

Reporting restrictions were lifted on Tuesday after a London jury acquitted three and convicted one in a case linked to a 16 million pound-plus ($20 million) freight forwarding contract related to a North Sea project called Jasmine.

FH Bertling executives paid more than 350,000 pounds in bribes to sweeten a bid for the Jasmine contract - and to ensure that inflated prices charged for additional services were waived through, the SFO said.

Former FH Bertling executives Stephen Emler and Giuseppe Morreale pleaded guilty to being part of a corrupt scheme to secure the contract.

Former logistics project lead Christopher Lane pleaded guilty to a separate bribery scheme involving overcharging and Colin Bagwell, another FH Bertling manager, was convicted by the jury of the same offence.

The men will be sentenced on Dec. 11.

The latest convictions come on top of seven others for bribing an agent of Sonangol, the Angolan state oil group, last year. Two individuals were charged over both schemes.

“These senior executives failed to show any integrity, resorting to bribery to secure lucrative contracts and hide their illicit activities,” said SFO head Lisa Osofsky.

“It is our mission to bring criminals like these to justice. Bribery has no place in business in Britain or abroad. It undermines the rule of law, distorts our economy and damages the reputation of the UK.”

FH Bertling Ltd (UK), once part of 150-year-old, Hamburg-based Bertling Group, went into voluntary liquidation in 2018.