Comment by skissane

The monarch has real genuine powers, and real discretion in how to exercise them, in the case of a constitutional crisis. Constitutional crises are rare, but they do happen. Consider a case from Australia - the dismissal of the Whitlam government in 1975 by the Governor-General Sir John Kerr. That is an example of a Vice Regal official exercising real, discretionary power. If the same situation had happened in the UK instead of Australia, the discretion would have resided with the Queen personally, as opposed to with her (largely indepedently acting) representative. Even in Australia, it is plausible the Queen could become involved in a 1975-style situation. If Whitlam had suspected Kerr was going to sack him, he could have tried to sack Kerr first. If there was a race to sack each other between the PM and the Governor-General, the Queen would have to personally decide how to react. e.g. if the PM advises the Queen to sack the GG, and immediately after that advice but before the Queen acts on it, the GG sacks the PM, should the Queen act on the request of the just sacked PM to sack the GG, or refuse? What if the GG advises the Queen to not sack him/her after all, or immediately appoints a new PM who conveys the same advice? Ultimately, whatever she did in such a scenario would be her personal decision, and it is unlikely that any court (whether in Australia or the UK) would entertain overturning it.