The problem may arise, though, when elections to the devolved parliaments are fixed term, but a Westminster GE is forced when a government collapses...and the two coincide or one occurs weeks after the other. (That's assuming that there are devolved parliaments to worry about by then....) One occasion arose when the Holyrood election was postponed for a year to make way for a Westminster GE. That led to a six-year term. Is this the only answer?