Which in our flat means mouldy ceilings.
I gaze up at it as I lie in bed each morning. No more peaceful lie-ins, instead I watch it's spidery progress, and plot its demise.
Years past have seen me don the rubber gloves and head into battle with bleach. That brings instant gratification, but no long-term satisfaction. A few weeks later I'll wake up, look up, and there it is again.
So this year is going to be different. First step: off to the internet for a bit of research. Where I find that the mould has been laughing at me, in between burps. Yes, bleach takes away the colour, but behind its cloak of invisibility the mould lies impervious. Worse, it's able to digest the bleach, and so when it gets its colour back it's stronger than ever.
The truth about mould's appetite for bleach comes courtesy of Mycologia's Mistress of Mould, Dr Kemp . She says to put down the bleach and turn to ... vinegar! And not just any vinegar. Apparently the supermarket cheapy won't be any use: "only white fermented vinegar seems to work, as synthetic acetic acid does not appear to be effective". Who'd have guessed?
So, last week I donned the gloves again, but this time set to with cloth and a bottle of the finest white wine vinegar. Initial results were mixed. There's no post-bleach-fumes sore throat, which is a major plus. But on the other hand the house smells like a chip shop. Never mind, the authentic chippy aroma is a small price to pay if the mould stays away.
One week later and there's mould again, but it's mostly in places that didn't get a wipe last week. So, they've been given the vinegar rub-down too. We'll know in a few weeks whether victory is mine.
Readers, any other solutions to suggest?
 - Mycologia Pty Ltd's 'Myths about Mould' page