A computer apparatus for creating a trusted environment comprising a trusted device arranged to acquire a first integrity metric to allow determination as to whether the computer apparatus is operating in a trusted manner; a processor arranged to allow execution of a first trust routine and associated first operating environment, and means for restricting the first operating environment access to resources available to the trust routine, wherein the trust routine being arranged to acquire the first integrity metric and a second integrity metric to allow determination as to whether the first operating environment is operating in a trusted manner.