P & Q gained ISO 9001 : 1994 certification from Quality Management Systems International plc on 17 September 1998. This involved an appraisal of P & Q's existing Quality Assurance practices and procedures, and resulted in the creation of Quality Assurance and Quality Procedure Manuals.

Twice-yearly Internal Audits are carried out to ensure that the documented Procedures and their associated Working Instructions are being followed.

Regular Management Review Meetings are also held to discuss quality-related matters, so that deficiencies can be highlighted and the necessary remedial action implemented. The Procedures themselves may also be reviewed and modified appropriately, both to reflect current practice and to tighten up Procedures and/or Working Instructions where deficiencies have been discovered. The Quality Assurance and Quality Procedure Manuals are currently being revised to conform with BS EN ISO 9001 : 2000.

An External Audit is carried out annually by Quality Management Systems International plc.