All of the paper manufacturer's pulp and paper products are now guarnateed to have used fibre from forests that are managed responsibly.

Previously, each UPM paper mill had its own Chain of Custody (CoC) certification, but the new multi-site certification means they are now replaced with two multi-site certificates, PEFC CoC and FSC CoC.

Will Stone, UPM head of communications UK & Ireland, said: "Multi-site CoC has been possible by replicating a best practice CoC management system across the business that will simplify the tracking process and systems auditing.

"It will mean that there is one common system operating in all UPM units, which will make it easier for us to monitor the levels of certified fibre at a company level and make it easier for future development to be implemented across all sites."

According to Stone, the move means there is no weak link in UPM's paper supply and that all mills meet the requirements of the FSC-controlled wood standard.

"UPM can now demonstrate that 100% of virgin fibre used at our mills originates from legal and non-controversial sources," he added.