GridPP operates a Grid for the UK particle physics community that is fully integrated with the Enabling Grids for E-sciencE (EGEE) and LHC Computing Grid (LCG) projects. GridPP provides CPU and storage resources at 19 sites across the UK, runs the UKIreland Regional Operations Centre for EGEE, provides Grid-wide configuration, monitoring and accounting information via the Grid Operations Centre, and provides support directly for its own system managers and users. This paper discusses GridPP-wide performance and accounting methods. Over the last three years, a prototype Grid has been developed and put into production with computational resources that have increased by a factor of 100. In the last year more than a million jobs were processed and accounted on the system. In 2006 performance is being improved with emphasis placed on the improvement of data management and file handling across the Grid.