This means the Irvine-based paper mill is now certified to both Programme for the Endorsement of Forest Certification schemes (PEFC) and Forest Stewardship Council (FSC) Chain of Custody standards.

UPMs executive vice president resources Markku Tynkkynen said the move was part of UPMs aim of increasing the use of certified fibre in all its mills.

In Scotland we want to investigate the functionality of the different standards in practice, he said.

Tynkkynen said the double certification would provide an opportunity to compare the two certification standards on an unbiased basis.

At present 12 UPM mills have been certified with a Chain of Custody system.