On Gardeners’ World, Adam chewed a sprig of coriander he had plucked. “It still tastes like washing up liquid,” he commented. It was not hard to imagine the sort of soapy taste he sought to describe.

Oddly, there is not a single moment that I can recall tasting washing up liquid. Perhaps there were traces on a mug, or on cutlery, just enough to convey the flavour of detergent, just enough to allow a sense of what fresh coriander might taste like.

There are tastes from years past which had a strength, a piquancy, sometimes a repulsiveness, that leave a lingering impression in the memory.

Sometimes the taste came through the inhalation of a scent or of fumes. Sometimes there were noxious fumes which left traces of a taste in the throat.

At school on Dartmoor, the central heating boiler was critical to making conditions tolerable in the winter. As it was, there would be ice on the inside of the bedroom windows in the morning. Without the heating the sub-zero temperatures would have taken a heavy toll on the more frail of the students. Yet the boiler emitted fumes that could almost be tasted, they would catch the chest, the throat, and seem almost solid. A scent of such fumes today is always immediately evocative of the school boiler.

Another substance with a very distinctive scent and taste was creosote. I spent the summer of 1977 painting wooden chicken houses with creosote. These were not the sort of chicken houses that someone might have in their garden, they were buildings each of which held thirty thousand battery hens.

Creosote could be a dangerous substance, but apart from an old pair of overalls and a pair of thick rubber gloves, I was given no protective equipment. The creosote would get onto my arms, my hands, my face. It would sting and stain, but, most of all, it would leave a sensation of smell and taste. Workers at the egg farm would joke that I had spilled so much over myself as I stood on a ladder trying to reach the tops of the wooden walls that I should be preserved for years to come. The rare smell of creosote now brings a taste at the back of my throat.

As soapy as coriander may taste, it is a pure and healthy plant. The taste of carbon monoxide fumes and the inhalation of creosote were but two examples of tastes that were not only unpleasant, but could be plainly dangerous.