A trusted research environment (TRE) is a secure environment in which researchers who have permission can analyse the data. TREs work on the basis that data should not be sent to researchers but instead researchers securely login to an environment where they can analyse the data. The data cannot leave the environment. All that can be exported is aggregate level anonymous data, such as a table or graph summarising the results. There are no accepted definitions for a TRE and many are run differently. The Goldacre review has sought to set out a vision for TREs going forward.