Tea-tasting is an unchanging process; Wilson Smithett was founded in 1865 and the generations of tasters have followed a very similar ritual for the past 133 years. But in other respects, the tea industry is rapidly evolving. Tomorrow, the last London Tea Auction will take place; from then onwards, most sales will happen via e-mail. "It's a sad day because it is the end of an era," says Tim Clifton. "But like many of the old trade practices, changes in communications and technology have made it outdated." Even the familiar, traditional wooden tea chests are fast disappearing, replaced by cheaper, more environmentally-friendly sacks.
Tomorrow's final auction has long been on its way. "There has been a gradual swing towards e-mail for years," says Mr Clifton. "The quantities at auction have been going down and down - people don't want to spare the time to go to the auction."
A tea auction, he explains, is "a very gentlemanly affair; not like a tobacco auction". Tea was first auctioned in London by the East India Company 311 years ago; the first auction specifically dedicated to tea took place in 1706. The earliest auctions were held quarterly and the tea was "sold by the candle"; as each lot was announced, a candle marked off in inches was lit, and the hammer fell on each lot as the inch-lines were reached. By the beginning of this century, there were auctions nearly every day of consignments from China, India, Ceylon and Africa. (Today more than half of the tea drunk in the UK comes from Africa.) The only interruptions were during wars. Now much of the tea is sold before it even reaches this country and the London Tea Auction is to close.
This does not, however, mean that tea is any less popular. Tomorrow the Tea Council will publish its annual report, which shows that tea remains the most popular drink in Britain. Three-quarters of the population drink tea, an average of 3.39 cups a day (more than double the amount of coffee). A report the Council has commissioned suggests that tea drinking is good for health: drinking between four and five cups a day could reduce the risk of coronary heart disease, and tea also contains antioxidants, minerals, vitamins and natural fluoride - and no calories.
But the main reason for the British love affair with tea is that we like it. "It's a splendid drink - and part of our national heritage," says Mr Clifton.
When the East India Company first brought tea to Britain, it was exclusive and was sold in London's fashionable coffee houses. At court in the 1660s, tea drinking was introduced as the de rigueur social habit by Queen Catherine, wife of Charles II, and gradually grew to replace ale as the "ladies' beverage". Samuel Pepys records, on Sunday 25 September 1660, that he tried "a cup of tee (a China drink) of which I never drank before".
The ritual of afternoon tea was established in the early 1800s, supposedly by Anna, Seventh Duchess of Bedford, who found she was too hungry to wait for dinner and began the tradition of serving tea and light food between four and five o'clock. Then came tea gardens and tea dances, tea shops and tea rooms, as tea became a drink for the masses. Even before the age of e-mail, speed was of the essence. The swift and elegant triple-masted tea clippers rushed the leaves back to auction in London throughout the mid-1800s.
The samples which flood every day into the offices of Wilson Smithett from all over the world are the leaves of the Camellia Sinensis. The plant is native to China and parts of India, but today it is cultivated in more than 25 countries. The leaves are left to wither naturally after harvesting, broken to release the natural juices and left to ferment or oxidise naturally, then dried, sorted and packed; the only added ingredients are aromas such as the oil of bergamot used to flavour Earl Grey.
Brokers then take over, checking quality and flavour and finding a buyer. "We work on behalf of the plantations, finding the best market for the chap's tea," says Mr Clifton.
The tasting is similar to wine tasting, a noisy slurp, swill and spit. Tim samples a high-grown Rwandan and pronounces it "very bright, with useful colour and strength - it's got briskness to it, it's a very attractive tea". He and Michael have worked together for 20 years and rarely disagree, though sometimes, says Michael, the teas have "very elusive characters". The tasting room's wooden benches and wooden drawers are all crammed with little metal boxes full of tea samples. Of today's samples, some are fibrous, some are dust-like, some are tawny-red, some dark brown. The smell is wonderful. The teas that make the grade will be sold and shipped off from their plantations to their buyers. The British are the only tea drinkers who habitually add milk, and have done so since the 1660s. Tim Clifton's own favourite, he says, is nothing fancy - "a thick, English, gutsy cup of tea".