If you'd like a reference it's
JAR-FCL 1.080
(v) A remarks column will be provided to give details of specific functions e.g. SPIC, PICUS, instrument flight time*, etc.
* A pilot may log as instrument flight time only that time during which he operates the aircraft solely by reference to instruments, under actual or simulated instrument flight conditions.
Details of all flights flown as a pilot shall be kept in a reliable record in a logbook format acceptable to the Authority
Logging of time
(1) Pilot-in-command flight time
(i) The holder of a licence may log as pilot-in-command time all of the flight time during which he is the pilot-in-command.
(ii) The applicant for or the holder of a pilot licence may log as pilot-in-command time all solo flight time and flight time as student pilot-in command provided that such SPIC time is countersigned by the instructor.
(iii) The holder of an instructor rating may log as pilot-in-command all flight time during which he acts as an instructor in an aeroplane.
(iv) The holder of an examiner’s authorisation may log as pilot-incommand all flight time during which he occupies a pilot’s seat and acts as an examiner in an aeroplane.
(v) A co-pilot acting as pilot-incommand under the supervision of the pilot-in-command on an aeroplane on which more than one pilot is required under the type certification of the aeroplane or as required by JAR–OPS provided such pilot-in-command time under supervision (see (c)(5)) is countersigned by the pilot-in-command.