Ar hyn o bryd, dim ond unwaith mewn unrhyw gyfnod o bum mlynedd y gall prif gynghorau gynnal refferendwm. Fodd bynnag, mae i'r sefyllfa bresennol botensial o hyd i greu cryn ansefydlogrwydd gwleidyddol gyda’r hyn a allai olygu newid yn nhrefniadau’r weithrediaeth yn ystod pob cylch etholiadol.
Currently, principal councils can only hold a referendum once in any five year period. However, the current situation still has the potential to create considerable political instability with what could amount to a change of executive arrangements during each electoral cycle.