The HPA sites at Chilton, Leeds and Glasgow offer a high quality instrument testing service for the test before first use and periodic testing of dose-rate monitors, contamination monitors and active personal dosemeters. In addition the Radiation Metrology Group at Chilton has one of the most comprehensive range of test facilities in the UK and holds UKAS accreditation for gamma dose rate measurements. The Radiation Metrology Group provides a range of services including instrument development and type-testing, the design of bespoke monitoring systems and also an independent assessment service for de-licensing and decommissioning work for UK regulators and others. Our customers include major corporations, industrial organisations, hospitals, universities and local authorities. Our staff have a wide range of practical expertise in the use of radiation monitors in the workplace. The Radiation Metrology Group at Chilton is a founder member of the Ionising Radiations Metrology Forum (IRMF) and provides significant input into national guidance on instrument testing, as well as taking part in IRMF comparisons. These IRMF comparisons provide confidence and ensure consistency of measurements. The comparison results are published by The National Physical Laboratory (NPL).