My upstairs neighbours are terribly nice, but too naive to be allowed to renovate their flat in peace.

The two brothers in their twenties bought the apartment together and are doing it up, I suppose, because they hope to sell and divide the spoils so they can buy one flat each. Such are the struggles of the younger generation to get on the housing ladder, and their efforts are laudable. They are young, idealistic and full of enthusiasm.

However, it would be much easier for all of us if they would listen to me when I try to explain to them that doom lies around every corner and nothing is more certain than that things can always get worse. Midway through their renovations, the brothers are still labouring under the misapprehension that the plumbing in our turn-of-the-century building is an inanimate object.

I have told them time and time again that the plumbing is a malevolent, scheming entity, intent on wreaking as much havoc as it can. But they won’t have it. They blithely continue to project manage their improvements without taking into account that they are dealing with pure evil.

When they began a year ago, they came down and sat in my living room and with perfectly serene faces outlined plans to remove from their loft the water tank supplying my bathroom and theirs and to put me and them on mains live water.

‘Are you mad?’ the builder boyfriend said. And then, speaking very slowly so there could be no misunderstanding: ‘If you touch that tank the pressure will go haywire. If you put us on mains live it will burst apart the pipes and everything will explode.’

He was laying it on a bit thick but we wanted them to back off before the monster of Victorian south London plumbing was unleashed. ‘Trust me. Don’t touch it,’ said the builder boyfriend. ‘That way madness lies.’

‘But we want to make more space so we can vault our kitchen ceiling,’ said one brother. ‘We want down-lighting,’ said the other.

‘That’s as may be,’ I said, as the builder b took on the blanched look that precedes a tirade of geezer-ese. ‘But the fact is, the tank that feeds my bathroom is in your loft and my lease includes a clause giving me demised rights over the loft so if you touch anything there you will have to pay my solicitor to insert a deed of variation in the lease.’

Saying such things to two twentysomething brothers hoping to turn a quick profit so they can move in with their girlfriends was like making white noise. They stared back blankly as if they didn’t hear.

‘We want to vault the ceiling,’ said one. ‘We want spotlights!’ said the other, sounding very much like Andy Pipkin of Little Britain’s Lou and Andy.

So we gave up and I put my concerns in an email stating that in no uncertain terms were they to change anything about the water without further consultation.

The next thing we heard was months later when one of the brothers texted to say they weren’t going to bother doing anything except install a new kitchen and bathroom.

As the bathroom went in, water duly poured through my ceiling prompting a three-week battle to find the malfunctioning pipe.

‘I told you, didn’t I? Evil, see?’ The poor souls scratched their heads while surveying their perfect bath tub with its gleaming taps that were now maliciously destroying my ceiling.

It had to be ripped out and reinstalled, of course. Then all was quiet for months, until the brothers informed me they were going to start on their kitchen.

An epic period of banging and clattering ensued, during which soot shot out of my fireplaces, damp patches appeared on my walls and, as the chaos entered its fifth week — and I was on the verge of contacting them to say I could no longer believe that a kitchen was all they were doing — my shower gave up and the pressure went in all my bathroom fittings.

I rang the head brother and let rip. ‘Come on, fess up and admit you’ve gone into the loft after all,’ was the essence of my rant. He insisted they hadn’t. But they had clearly done something.

On their say-so, I went upstairs and nosed about but the tank was still there and I couldn’t see anything obvious. Their builders were upset, accusing me of being rude to them. ‘Diddums,’ I retorted, and called in that living legend, Tony the plumber, who began by dismantling the shower unit.

A week later and he has unravelled the bathroom to the extent that there is literally nothing left. Some £500 worth of fixtures and fittings are on order. And I’m on Rightmove looking at ranches in Montana.