Despite Ludwig Wittgenstein's assertion that "death is not an event in life", it is almost the defining quality of humanity that we regard it as highly significant.

We are almost unique as a species in being aware of and anticipating our own deaths, and funerary customs may well be the oldest human trait, dating back at least 50,000 years, and perhaps twice that long. (Whether the Neanderthals buried their dead, for which there is some evidence, is a topic of hot dispute amongst archaeologists and anthropologists.)

But whether the arrangements we make for what happens when we die are as elaborate as those of the Pharaohs or as prosaic as taking out an insurance policy to pay the Co-op, mankind surrounds death with ritual. In part, what is being acknowledged in a funeral is that the deceased was once a person, but no longer is; that – no matter what beliefs or lack of them anyone has – they have entered a different category from those of us still alive.

Naturally enough, the prominence accorded to those whom the world considers important persists in death as in life, though the rest of us can console ourselves with the thought that we are still above ground. There have, however, often been voices warning of the illusory nature of such memorialisation. Shelley's poem Ozymandias is a deliberate reminder that worldly glory does not survive, though you may feel the point is rather undermined by the fact we do still remember who Rameses the Great was, and that the Valley of the Kings is still there to remind us of him.

On the face of it, then, it should come as no great surprise that Baroness Thatcher's funeral arrangements are of a fairly grand order. Even those who couldn't abide her (of whom, as we have been reminded during the last week, there is an abundant supply) shouldn't have to think very hard of the reasons.

She was the first woman Prime Minister; she was, by a very considerable margin, the most prominent British politician in terms of international reputation for at least the past half-century; she was the longest-serving premier of the 20th century; and she led the country during the successful Falklands conflict. All of that has to be conceded before one even considers the radically transformative effect of her time in office.

I doubt anyone's prejudices for or against Lady Thatcher have been much altered by the acres of newsprint devoted to her legacy this past week, so I don't think there is much to be gained at this point by arguing about whether the changes she wrought were necessary or desirable. But the shift in politics from the 1970s is demonstration enough that they were significant; the Thatcher governments may have made little effort to occupy the centre ground, but they were successful in shifting the territory which could be described as the centre.

So it seems self-evident that her funeral was always likely to be a big affair, with statesmen flying in from around the world to pay their respects. Booking St Paul's for 2000 people doesn't look over the top. And, given the combination of the British public's enthusiasm for spectacle, the large numbers of people who admired her and want to pay their respects and (no doubt) the large numbers of Socialist Workers and other lefties who'll want to mark the occasion with some sort of protest, the funeral cortege was always going to require a lot of organisation and policing.

And yet, despite all that, I think the arrangements for Wednesday have overstepped the mark. A state funeral – and whether one bothers about the technical differences between a "ceremonial" and a "state" funeral, this service, like those of Diana, Princess of Wales and the Queen Mother, is a state funeral in all but name – is going too far. Worse, it will be damaging, not merely to the general mood of the nation, since public opinion is so sharply divided, but ultimately to the Conservative Party, Lady Thatcher's own reputation and the traditions and institutions which surround events of this sort.

And I think this point ought to be conceded even by her most fervent admirers. Though I happen to think she was a greater Prime Minister than Clement Attlee, he is at least a comparable figure in terms of having transformed the country, while Harold Macmillan and Harold Wilson both served more than one term and had long, dominant, public careers. None of them received a funeral of the sort being planned for Lady Thatcher.

Churchill is a special case, of course, as a wartime leader. And though I was then and am still proud of Lady Thatcher's stance in defending the Falklands after the Argentine invasion, it is ludicrous, indeed insulting, to compare her role then with the part Churchill played in a worldwide conflict during which the nation (and the world's) freedom and survival were at stake.

But otherwise, I think the last politician self-important enough to have a public funeral was Gladstone. Typically, he regarded Disraeli as a show-off because he had refused to have a state funeral, preferring to be quietly buried beside his wife. Of course, it has to be admitted that Disraeli was a show-off, but he at least demonstrated that you don't need a huge jamboree to cement your place in history.

Unfortunately, there is every danger that Lady Thatcher's funeral, however well intentioned, will degenerate into a huge Tory jamboree. That would not reflect well on the party nor, I suspect, do it any favours with the electorate. There is an equal danger that it will be marred by violent protests. In either case, however, the Queen would have been better advised to refrain from attending.

I have my own suspicions about why this funeral has been organised as it has, however. The arrangements – in case it's slipped your mind – were, after all, decided and set in place under a Labour government. Can it be that it sets a useful precedent to award a ceremonial public funeral to Prime Ministers who have won three elections and taken the nation to war? I wonder if Tony Blair might possibly be thinking, as in the end we all must, about the inevitability of mortality, and what happens next.