Even if you don't find a UTC entry in your system's list of timezone values, setting
TZ=UTC0 will set the timezone to coordinated universal time with no summer time shift. You can set it in /etc/environment (or some other system dependent file depending on which operating system you use) to affect everyone that logs in after you make the change, in your home directory's .profile (or other startup file depending on which shell you use) to affect all commands in login sessions you start after you make the change, or as a prefix on a command line (e.g.,
TZ=UTC0 date) if you just want to affect that command.
PS The UTC comes from a compromise between the English Coordinated Universal Time (CUT) and the French Temps Universel Coordonné (TUC) reached by the International Telecommunication Union to have a common, worldwide abbreviation for this timezone.