Fail to renew your public liability insurance at your peril, as this dreadful tale of a family-run electrical firm, a little old lady’s bungalow and some (possibly) poorly rigged festoon cabling proves

My electrician is a really good chap. Runs the family business using a handful of good lads who all know their electrical onions. So I’m not sure I should tell him this story about a similarly well established electrical contractor firm owned and run by Eric Harbour.

The years have rolled by and Mr Harbour is nearing retirement. His knee gives him gyp so another electrician, Roy White, who’s younger but very experienced, gives him a hand.

It was during an ordinary rewiring job in Mrs Drake’s fifties bungalow in Saltdean, East Sussex, that disaster struck. After the 93-year-old lady decided to leave the electricians to it and visit friends in North Wales, the fire brigade was called out to her house at 3am on 27 June. The roof was burned to a cinder – and you can imagine the rest of the damage to the house.

"The heaters are nice and toasty but they're pongy like fish."

The problem was that not only had Eric Harbour’s public liability insurance expired but it was almost impossible to prove what had caused the fire. And the bill for the damage came in at just short of £100,000, to say nothing of the legal costs. For a man facing retirement after a lifetime of electrical contracting, this was not a happy prospect.

As was pointed out during the court hearing, there was something fishy about the events leading to the fire. This took me back to my childhood – not to my mother’s love of cod but to the pong in our old house, especially in winter, when we plugged in the umpteenth electrical fire to the double adaptor plugged into the triple adaptor plugged into the wall. Heaven knows how close we all were to perishing in a grand conflagration.

The fishy smell was one of the clues investigated for the cause of the fire. So, too, was the temporary works lighting that had been rigged up in order to do the rewiring work once the bungalow’s electrical system was switched off.

The two electricians had used a festoon cable, which consists of two sheaths of cable each containing live wiring. I remember years ago fixing up a run of illuminations for a village fete using one of these. The bulb holder had two sharp prongs, which were jammed into the festoon cable and screwed home. Then the bulbs were simply plugged in.

One expert thought the single lead light left on with a 100W bulb was responsible for the fire. Another pointed to the festoon as the cause

Nobody, as far as I can see, criticised this bit of equipment. The experts said in the trial that festoons were safe and the festoon had been hung up in the bungalow’s loft to provide light to work by. Also used was a single one-bulb lead light for close-up work. One expert thought the single lead light with its 100W bulb was responsible for the fire. Another pointed to the festoon as the cause.

It was interesting to see how carefully the investigation into the cause was conducted. Had the place been left open all night and invaded by idiots? Did the idiots set light to the place? Why, if the power was off, was there that fishy smell? Was it actually switched off? Did the roof loft contain combustible materials? Was the festoon and/or the lead light left on all night? Would two experienced electricians go home for the night and leave their lamps switched on?

One by one, the lines of inquiry fell away. In a court case or arbitration, every possibility has to be raised, batted and fielded. There was no sign of vandalism or idiot behaviour. Yes, a fishy smell can come from heated PVC or wiring, but it also crops up when old wiring is being ripped out. So the focus shifted to the lead light or festoon run.

First, though, was the vexed question of whether the temporary lights had been left on. If it had been winter, one or other electrician would have spotted that the lighting was still on as they were leaving. But this was mid-summer, so it could have been left on by oversight.

What of the stringing up of the festoon? One expert persuaded the judge that damage during fixing was a high probability, or at least as probable as other causes. And given that sole control of the bungalow was in the hands of the electricians, that favourite law student maxim res ipsa loquitur applies – that is, it speaks for itself who the culprit was.

In the end the judge found the electrician liable for the £100,000 cost of rebuilding Mrs Drake’s home. It was a situation neither the retiring electrician nor his 93-year-old customer needed at their time of life. The old lady was awarded £3,000 for her distress and inconvenience. Not much, is it?