Postcomm, the UK postal regulator, has found in an investigation that Royal Mail may have been in breach of its license since 2006.

It has been discovered that the identity of independent quality-of-service researchers, has been exchanged by some delivery office managers.

There were concerns that in identifying mail sent to panelists at Research International, quality of service targets could then be manipulated to show a higher performance target.

Postcomm said that while the exchange had not had a major impact on quality, Royal Mail had not to identified risks to compliance, in line with conditions in its license.