This is a twist on words of Greenwich Mean Time which
defines many Gambian's notoriously bad time keeping
i.e. nearly always late for an appointment. If you agree
to meet someone at for example 10am in the morning they
will most probably turn up at 11 or 12 am if they bother
to turn up at all!
tip is to call an individual before departing to meet
them at the appointed hour or else request that they
call you by phone when they are on their way.
If you are going to meet someone at their office then
do make contact with them by phone just before you depart
as they may have gone off on another errand or attending
some kind of unscheduled ceremony that morning.