 There are few greater luxuries in life than a piping hot bath. I shall never forget the deep relief of a tub laced with tea tree and lavender oil after the birth of my first child, or the joy of a peaty soak in soft Jura water after a hair-raising tussle with the Corryvreckan whirlpool. There is something about submerging the body in warm water that both calms and revives the mind.  In recent years, the delights of bathing have been made all the more piquant by the fact that baths have become a symbol of unecological profligacy, the kind of selfish behaviour that only the most perfidious of climate-change deniers would indulge in. The shower, with its brisk eco-efficiency and no-nonsense approach to bodily cleansing, has taken over.  But what's this? It turns out that certain types of high-tech shower are, in fact, much worse than the sinful old low-fi bath. They're not quick at all: the average shower lasts for eight whole minutes. They're not eco-friendly, either: research by Unilever has found that some showers use nearly twice as much water as the average bath: up to 136 litres compared with 80 for a bath. That amounts to 200,000 litres of hot water per year for a four-person family, at a cost of ?918. a lot of money down the drain.  Personally, I have always been suspicious of the shower's supposed superiority. Not just because of our house's quintessentially English plumbing (uniquely unsuited to showers: someone has only to flush the loo for the thing to go from warm to freezing to boiling in the space of a few seconds, leaving the unfortunate occupant of the cubicle squealing like a scalded cat); it's also that people who claim to prefer showers to baths are so unbelievably pleased with themselves.  "I'll just jump in the  