"You're overlooking the fact that what you describe as a 1000 year old system has evolved into a constitutional monarchy in which the Royal Prerogative is effectively exercised by the elected government. Likewise the Royal Assent is a formality, and if it were ever to be refused it would result in a constitutional crisis which the monarchy would surely lose."

As good an argument as any for actually getting rid of the monarchy. If their role is purely formal then it's time we and the representatives we elect took on the burden of these decisions ourselves rather than some distant figurehead who is utterly irrelevant to virtually the entire population, as well as ignorant of the problems and concerns her 'subjects' suffer on a daily basis.

". . . when we have a monarch, such as the present Queen, who shows judgement and wisdom in exercising her powers she can make a positive contribution, and those who do not show the same talents can at least do little damage. Could the same be said about a politician?"

Possibly not, but that's not really the point - the point is accountability. We get the politicians we deserve and it's quite within our power to rid ourselves of them if we wish. Unfortunately the same can't be said of the monarch or her ilk, whose sole qualification for the job is the fact she was born to it. She is the symbol of an unequal, class-based society, and really should be consigned to the role of curiosity for American and Japanese tourists (at her own expense).