"Perhaps - yes. But it's not a question of whether you wouldn't mind giving some of your winnings to charity, but whether you should have to regardless as to whether you mind or not. No one "deserves" a gift in any objective sense, just like no one deserves anything in any objective sense, because there's no one objective enough to decide that."
Maybe no-one deserves anything in the objective sense but you are the one who said that earned wealth represents a meritocracy which seems to imply that wealth has been gathered on merit and is, in one sense at least, deserved. I don't see why you are now moving away from that idea. I don't think that you would disagree that if you have two people, one who lives on benefits his whole life is suddenly gifted a million pounds vs one who works hard to earn a million pounds that the second character has in some sense deserved that money more. Earlier in this thread you described money taken in tax being given to people who hadn't earned it and didn't deserve it, now you are saying "deserve" doesn't mean anything.
Basically, now you're just going for complete moral relativism by saying "no-one is objective enough to decide that". As a society we agree to allow government to make moral decisions, this is merely another one.
"I was running with my analogy. say I spent thirty years working and saving money to donate to my favourite charity - my no-good, spendthrift son. During that time I paid income tax when I earnt the money. And then again when I give it to my son. You don't think my son deserves it. I don't think that's any of your business."
OK, you said it wrong, that's why I was confused. Above you implied that the son had already paid tax on it, not the father.
Anyway, back to the question in hand. Your argument basically comes back to "it's none of your business" - or "it's not fair" in other words - but you still haven't said why.
"Surely the important thing is how much you have grown your wealth. Simply inheriting a million and dying with the same amount doen't necessarily mean you were producitve in any way."
Well consider two sons. One, the son of a poor man inherits nothing, gets a job and earns £25k a year which he lives on, dying finally with nothing. The second, the son of a rich man, inherits a million which he banks at 5% per year, he lives on £25k a year and grows his wealth by £25k in the first year and more in the next year as the sum he is earning interest on grows. The gap between him and the poor man has grown each year even though he hasn't lifted a finger - do you really think that this is something that exemplifies a meritocracy?