The Commissioning Support Service (CSS) is an NHS healthcare organisation that works with Primary Care Trusts (PCTs) across L ... ondon to improve patient care through the effective selection and management of healthcare services. CSS is one of the founding teams of Commissioning Support for London (CSL), a new organisation which provides clinical and business support to London's NHS. To find out more about CSL please visit www.csl.nhs.uk. To strengthen and drive excellence in this work, CSS provides resources, tools and support to Commissioners (the people responsible for purchasing healthcare services on behalf of PCTs) and their activities across 30 PCTs in London. read more