The University ceased to use ATHENS, as a user authentication system, in 2008. This was replaced by Shibboleth, which allows us to use local authentication through University managed accounts.
ATHENS is currently used within the NHS which is supported through the Medical Library.
There is further information about this, here, but it should be noted that these accounts are for those employed by or undergoing research through the NHS, and not for staff and students at the University - unless they have a joint University/NHS appointment.