Tennis-goers eat two tons of them a day, but the Official Wimbledon Strawberry has a busy 24 hours before it's fit to appear on Centre Court

Late every evening during Wimbledon, when most of the players and spectators have left, in an area known as "The Slab", a cavernous chamber hidden from public eyes deep underneath Number One Court, a time-honoured tradition is enacted. It is the arrival of the Official Wimbledon Strawberry.

Late every evening during Wimbledon, when most of the players and spectators have left, in an area known as "The Slab", a cavernous chamber hidden from public eyes deep underneath Number One Court, a time-honoured tradition is enacted. It is the arrival of the Official Wimbledon Strawberry.

Or, more precisely, the Official Wimbledon Strawberries, since around two tons are unloaded each evening for consumption the next day at the world's most famous tennis tournament-cum-English garden party, where they will be eaten by a third of all visitors. In all they consume a total of around 23 tons each year. And while tennis stars may come and go, Wimbledon will forever be synonymous with this most English of summer fruits, an association that dates back to its tennis party origins in Victorian times.

But few of those scoffing their strawberries, sitting on the Tea Lawn or high on Henman Hill, will know of their journey from field to punnet, involving, as well as the hidden world of The Slab, young people from more than a dozen European countries, a personal security escort and the appetite of a carnivorous mite - all in just over 24 hours.

The story of each day's strawberries begins 45 miles south of SW19, amid the market gardens of Kent where, at about 5am every day, groups of pickers gather in the yard of Hugh Lowe Farms, near Mereworth, the supplier for more than 10 years of the Official Wimbledon Strawberry. As they wait to be bussed to the outlying fields, the talk is in the languages of countries such as Ukraine, Belarus and Lithuania.

These are not illegal immigrants working for some "gangmaster", but mostly young students, on a Home Office-approved scheme which allows them temporary work permits in order to help out growers at such times.

At 5.30am, they begin their seven hours of back-breaking work, stopping at 1pm when it gets too hot. Today, under a warm early morning sun, the 38-strong team picking the Official Wimbledon Strawberries are working an open field of row after row of plants, the bright red jewels peeking out from under the green leaves.

Each picker takes a cardboard tray, printed in the familiar Wimbledon livery of purple and green, fills it with the empty plastic punnets and ropes it to a plastic "sledge" which they drag alongside them. They have to squat or sit to pick, shuffling along at a crouch, using their bare hands. Wastage is high - because these are the Official Wimbledon Strawberries, pickers discard all that are damaged, attacked by bugs or misshapen.

They are paid £1.85 a tray. Kaija Prikule, 27, a trainee teacher from Latvia, confesses: "I don't really like strawberries, but I don't mind the work. Of course I know these are for Wimbledon. Everybody in the world knows about Wimbledon." A fast worker can net well over £100 a week, from which a deduction is taken for accommodation at the farm.

Standing amid the strawberry plants is Marion Regan, 43, a botanist by training who became the third generation of her family to run the farm. "I grew up surrounded by strawberries," she cheerfully admits. She says that there are no longer local pickers as there were when her grandfather began the business 100 years ago, so they now rely largely on Eastern Europeans, as they did on the South Vietnamese boat people a few years ago.

Although the farm is certified for some organic production, these strawberries are not organic. But the farm is a member of Leaf, a body that promotes high environmental standards such as crop rotation and minimal chemical use. It supports what Regan terms "beneficial insects". "A common pest we face is the two-spotted spider mite, which suck away the sap of the plants. They can cover a whole plant quickly. So we introduce something called the phytoseiulus mite, which is bigger and eats the spider mites and not the strawberries."

These are, Regan is anxious to stress, extremely well-tended, bespoke strawberries, eminently suitable for their final destination. "I've only been to Wimbledon once, a couple of years ago," she says, "I'm too busy normally. But it did give me a thrill to see all those people eating my strawberries."

The filled trays are driven to the packaging plant about a mile away, where they are checked, cooled and stored until collection.

The Official Wimbledon Strawberry is the Elsanta, the dominant variety consumed in Britain. It is, perhaps, the Pete Sampras of strawberries: a reliable performer, its regular shape and colour make it the favourite of growers, supermarkets and caterers - but it's criticised by some as being a little unexciting. While Wimbledon the tournament loves the exciting showmen, the Ivanisevics and the Agassis, Wimbledon the catering operation rejects anything a little unusual, however tasty.

However, Regan's Elsantas are both regular sized and extremely sweet and flavoursome, suggesting critics have been eating the wrong Elsantas or ones which have spent too long in supermarkets, since strawberries begin to lose flavour the moment they are picked. This is also why the Official Wimbledon Strawberry has to get to SW19 as soon as possible. At about 5pm, regular driver Andy Cameron, who works for wholesalers Peachey's, collects the pallets, each bearing dozens of trays, for delivery to SW19. Although he has been doing the job for more than 10 years, Cameron, 39, is still slightly in awe of the importance of his charge - "It's a prestige cargo, isn't it?" - and his journeys are fraught with one big worry: "I'd hate to be the answer to a Trivial Pursuit question - the one about 'who was the driver who shed his load and left Wimbledon deprived of strawberries?'"

This year he has extra worries: for the first time, all Wimbledon deliveries go through an external security checkpoint on the A3, about four miles south. The lorry is examined and a Securicor officer climbs on board as the escort for the final stretch. Cameron then has 20 minutes to reach his destination - often made difficult by the heavy traffic - or the security clearance is invalidated.

Somewhere between 8pm and 10pm, when the lorry finally reaches the grounds of the All England Lawn Tennis and Croquet Club, it sweeps through Gate One and down into a vast service tunnel. During the day, players take the right-hand branch to the changing-rooms, while at night it is the left-hand side that is busy - all the huge amounts of food and drink consumed at Wimbledon arrive this way.

Many metres below Number One Court, there is a huge space where all this is stored: vats of mayonnaise, crates of lettuces, trays of cakes, chickens and salmon. Here, each evening, on the loading bay, known to all as The Slab, Ben Joyce, 23, who works for the Wimbledon caterers, Facilities Management Catering (FMC), supervises the unloading of the day's deliveries into a huge walk-in cool room, where they are held until early next morning.

The warren of storerooms and kitchens underneath Number One Court is the domain of people such as Frank Coughlan, FMC's executive chef, dressed in immaculate whites, complete with hat. Coughlan explains that, while the chef in him wants to try new things with strawberries, the customers just want theirs with cream. "We do use them in other ways - we did a pan-fried duck with strawberry salsa the other day, and that was very successful. We've tried making things like strawberry fools, but people here aren't that keen - they just want their strawberries and cream, they outsell everything else."

But don't the hospitality suites of the big companies get a slightly better class of strawberry than, say, the Tea Lawn? The chef is adamant: "The kitchens get the same as the Tea Lawn, the same cartons packed in the fields - there's no need to discriminate because we know the standard is high."

So, early each morning, and about 24 hours after being picked, the trays of strawberries are distributed to more than 50 different outlets around Wimbledon. All the Official Wimbledon Strawberries cost £2 a portion - including cream - whether they are served to the public on the Tea Lawn, to officials in their cafeteria or to the debenture seat holders in their plush restaurants around Centre or Number One Court. In the Royal Box or the hospitality suites and marquees, the price is wrapped up in the set menus.

By far the biggest outlet is the Tea Lawn, where a series of tents and counters also sell Pimm's, champagne and, it has to be acknowledged, ice-cream, pizza and beer. And by mid-afternoon, regardless of what is happening on the courts, the area is packed. Behind the scenes, in a kitchen tucked away near Centre Court, is where the strawberries are taken from The Slab by tunnel and forklift, and readied for eating. More students, mainly female, sit around a table working their way through the stacked trays, hulling the strawberries, throwing out bruised ones and placing them in punnets. The Official Wimbledon Strawberry has to conform to a certain shape and size in order to fit around 10 spoon-sized berries into each serving carton.

This time there are predominately Home Counties accents and the talk is of boyfriends and last night's television. Like the others, Alice Cundell, 19, a geography student at Bristol University, is earning a bit of extra cash: "I heard about this through friends. After two weeks, you really don't want to see another strawberry for a very long while."

They rotate between this for two or three hours at a time and serving behind the counter. They all wear gloves because, as Greig Milne, the Tea Lawn manager says, if they didn't the stain would never come out. There is a bit of competition to see who can fill the most punnets, and Milne adds with a grin: "We have thought of getting someone in to read to them, like they do to the Cuban cigar-rollers, to see if it improves productivity." Cundell wrinkles her nose at the idea: "It's a bit of a mother's meeting, really."

In an office nearby, the next day's cycle is already beginning as Colin Botting, FMC's director of procurement, prepares the night's order for Peachey's. It varies slightly each day: good weather increases consumption, rain is bad for business because, although people tend to head for the tea rooms, they linger.

Meanwhile, this day's Official Wimbledon Strawberries are entering their final stage. Out on the counter, liberally covered with cream, about 30 hours after picking, they are sold to people such as Margaret Smith, 62, a retired care-home manager from Erith, making her first visit to Wimbledon with her friend, Ingrid Jones, 56, from Sidcup, a regular. I found them in the late afternoon, sitting on a bench in their waterproof macs, both wearing rather natty straw hats: two Kentish ladies half way through their punnets of Kentish strawberries.

"We've seen Mary Pierce and Goran Ivanisevic and it's been a lovely day. And now we're having our strawberries," says Mrs Jones. Her friend adds: "She's been nagging me for years to come, so I did and it's been fabulous." "And I was just saying," says Mrs Smith, a spoonful poised 'twixt punnet and mouth, "my day here would not have been complete without some strawberries. If I'd have gone home without having some, I'd have felt short-changed." She's clearly relishing every mouthful: "And they are lovely, really sweet, you don't need sugar do you? I might have a Pimm's next..."

And with that, she spooned one of Marion Regan's finest into her mouth. The Official Wimbledon Strawberry had reached its final destination.