The closest it comes to is the feeling I get around the start of every spring. Something odd in the air, a tightening of the wind, an unusual sharpness in the light, that sets a stirring inside me.

A new flush, a zing, a glow, an idea, I don’t know what, came in late January. It wasn’t the weather. I can’t pinpoint the day it settled on me. It took a couple of weeks to begin to articulate it. It was more the changing of the colour of litmus paper than a flash. Suddenly, I found other people fervently agreeing with me, and startled also that I should be feeling the same thing. That this year there is going to be change.

If you had said that to me in late December, I would have said, forget it, Robert Mugabe, just 83, will be bestriding Zimbabwe well into his nineties. Since 2000, when he began to hammer the life out of the first genuine, popular democratic movement in this country, despair has eaten into almost everyone.

But there is that thing in the air. It’s not just journalists, academics, lawyers and human rights activists unsettled by it. The youths in Epworth township south of the city who shout abuse at policemen — provocative behaviour unheard of till now — have been fired by it. The same sense moved the man arrested at a police roadblock at Hot Springs in the southeast for having a banknote with the words scribbled on it in Shona: “For Satan so loved Zimbabwe, he gave his only begotten son, Mugabe, that whoever follows him shall have everlasting poverty.” And the women demonstrators late last month who picked up teargas canisters fired at them by riot police, and hurled them back.

This flickering that shows itself in anger, boldness and hope has not had anything to do with a welling up of opposition political momentum, as there was in 2000 when the opposition Movement for Democratic Change had to be beaten and cheated out of election victory. The MDC has been split for almost two years and the separate factions are virtually dormant. The restiveness has grown by itself, spontaneously.

I can’t pinpoint why it should have suddenly begun to stir now, or at all. The incremental pressure of the struggle for survival under 1,600 per cent inflation, incessant harassment and brutality by Mr Mugabe’s many arms of repression, and the helpless outrage at being trampled on by a small class of ultra-rich venal parasites has to be at its heart. But the same motives have been there in other African tyrannies for decades, without producing a twitch of unrest.

Zimbabwe has passed an indefinable tipping point. It is an elusive, completely unpredictable and fragile phenomenon; Mr Mugabe has already set out to extinguish it, and he knows no civilised limits.

But it can also be as terrifyingly infectious and destructive as the ebola virus.

Times Recommends

• It’s the beginning of the affair
• Afghanistan: still a price worth paying
• Heroes of the downtrodden