The SATRE DARE UK-funded Driver Project was challenged to create a trusted research environment (TRE) architecture supporting the research community's need to have suitable data analytics and research environments for working with sensitive data. The project developed an inclusive and transparent way of working to ensure that what was created was representative of the TRE community in the UK. We have created, for the first time, an open specification for TRE operators by which to evaluate themselves against a set of capabilities. It is a thorough specification, perhaps definition, for TREs informed not only by the experience of the project team who have been running a TRE and supporting sensitive data projects for a combined 15 years but al...