No. No. No. And also: no. Not even: no thanks. Not later or maybe or let’s see. This is simply a hard, flat no. And indeed an angry and reproachful no, too. When it comes to the ICC’s suggestion that four-day Test matches may be the future of international red-ball cricket there is only one sensible response. That response is an aggressive, concerted and righteous rejection.

This is an informed no, too, a no that understands we live in a sporting world dominated by greed and short-termism (otherwise known as the commercial or “real” world). Change and compromise have been the dominant notes of cricket’s evolution over the last few years. A great many lines that shall never be crossed have already been cheerfully discarded, often with no harm done in the process.

Four-day Tests might look like something similar from this distance. A bit of a do about nothing. Just another dimly felt note of contraction. How much easier simply to shrug and move on.

Except this is something else entirely. The four-day Test goes to the heart of the most basic question facing this delicate, enduringly beautiful sport. Does cricket exist to make money or make money to exist? Make no mistake. The shift to a four-day game, driven purely by the lure of reducing expenditure, would end Test cricket in its current form. So much for all the talk. Here it is. The real death blow.

Never mind the obvious point that snipping off the fifth day would automatically cancel the majority of great Test matches played to date, not to mention every single great Test draw (apologists will point to the possibility of the great four-day draw taking its place. Again: just no).

Never mind the death of comparative statistics, the loss of Test cricket’s narrative strand, the heritage wastage. Above all snipping off the fifth day would end something intangible, the fine balance of tensions that distinguishes the five-day Test from all other forms of sport; perhaps even all other forms of shared public activity.

Need some proof? Cut to Cape Town and England’s gloriously hard-won victory in the second Test against South Africa. Sometimes sport has a way of telling you things. In the week that the ICC’s plans have been rejected – hearteningly – by Virat Kohli, when there is a sense of traction being sought for this act of pure sporting vandalism, cricket cleared its throat and dished up a five-day Test of brilliantly sustained and engrossing drama.

This is not just about the final day. To get a proper feel for the value of Test cricket’s span it is necessary to look back down the timeline. To admire in particular Dom Sibley’s maiden Test hundred on days three and four, an innings that feels in its way like a slow-burn, perfectly timed two fingers to the basic idea of the four-day Test.

Dom Sibley takes a stump to celebrate his century. Photograph: Stu Forster/Getty Images

Consider the sleek, adrenal beauty of that slow, crabby innings. Sibley took 411 minutes to get there. He played the ball so late it was almost in the slips by the time his defensive bat made contact. Sibley finally produced a sweep shot when he was on 99, but only because it now made sense to do so with the field up. His refusal to be hastened, to alter his tempo, to be diverted from the process was glorious, and indeed deeply moving.

There was development here, too, subtle shifts of angle and intent. Sibley appeared to have no off‑side game at all in New Zealand, to stand at the crease like a blinkered horse, unable even to see half of the outfield.

In South Africa Sibley has moved across his stumps, given himself the freedom to nudge an off-side two, to apply the odd scathing cut. This wasn’t a six-and-a-half-hour hundred. It was a month-long hundred. And it bloomed in the shadow of that fifth day, in the sense of time in store, freedom to breathe and manoeuvre the day, the game, the opposition into his path.

This is the key point. Yes: five days rarely happens in practice. But the entire tone and texture of the game flows backwards from its possibility. Take it away and there is no Sibley hundred, or at least not this Sibley hundred. Take away the fifth day and that endlessly varied tempo, the sense of depth, of layers in reserve, is destroyed for ever (not to mention the entire thing wiped out with a bit of rain).

Take away the fifth day and you take away the need to build in all those variations: the essential nature of spin bowling, the diversity in team roles, the beauty of changing pitches, weather and physical capacities. Take away the fifth day and you may as well chuck out 20% of Monet’s paintings of Rouen Cathedral because, let’s face it, we’ve got enough of them to know what it looks like anyway.

Here’s another point the profit and loss account won’t reveal: slow things are good. Slow change, frustration, dullness, lost half‑hours. Test cricket tells us about life, that there are periods of death and slackness and frustration. The most unforgettable moments in this sport – and thereby in all sport – are functions of this. Jack Leach running a single. Monty Panesar blocking for half an hour. These are, without context, banal interludes. In context they become irresistible, powerful, in ways that can’t be staged or forced or hurried.

Yes, change is necessary. Change is often a good thing in its own right. T20 as a gateway to Tests, all forms interlocking and feeding into one another: this was the model we were sold, one that still makes plenty of sense. Here we have the reality. There is no argument for creating a four-day Test that isn’t to do with saving money.

A four-day Test would save on broadcast logistics, staff hires and fixed costs of every kind. But it would do absolutely nothing for the sport itself, would instead cheapen and subtract in ways that can never be put back.

Five days of Test cricket: this is an improbable kind of beauty, something that wouldn’t get past the first pitch meeting now. And yet it remains for all its fragilities the best form of the best sport; an entity that can only be destroyed or preserved from here. Time to pick a side.