Christ died on the cross, then rose again to complete the mystery of our salvation and redemption. His victory over death is at the spiritual heart of the whole narrative of Easter. So how come the most prevalent symbol of this monumentally significant festival is the chocolate egg? Not that Christianity is alone in making the connection between religious occasions and confectionery. Hindus celebrate Diwali with brilliantly coloured sweets and sugar statues of the deities; Muslims gorge Turkish delight at the end of Ramadan; Jews dream of a land flowing with milk and honey. The Buddha himself is thought to be descended from sugar cane.

"God must have a sweet tooth," Sanjida O'Connell remarks in her exhaustive new study, Sugar: The Grass that Changed The World. "Sugar cane has been transported, almost without fail, throughout the world by men and women carrying faith and this overgrown grass." Jesuits brought sugar cane to America during the transportation of slaves to the Caribbean and introduced new refinery techniques from China. Muslims spread precious recipes for sugar production across the globe, while the Jews, serially banished, would bring their knowledge of sugar refining to each new country.

Sugar has come to symbolise godliness around the world. In China, fasting monks and nuns would drink sugared water, and would worship the Buddha with a sugar ceremony. Nuns in Europe fashioned sweets in the shape of female genitalia and virgins' breasts - in honour of Saint Agatha, whose breasts were cut off. An obscure mediaeval sweet, manus Christi, or 'the hand of Christ', rested on the belief that a sweet could save a life, while early sugar boilers would recite the Ave Maria to time their recipes.

But while sugar is universally regarded as holy, it is simultaneously the very epitome of evil.

For a start, its very origins are shameful. It was the lust for sugar that was responsible for some of the most extreme obscenities of the slave trade: the sugar plantations in the West Indies were spectacularly brutal and cruel even by the base standards of the rest of the system.

Paradoxically, the leading English sweet manufacturers of the 19th century were pacifist Quakers who had deliberately sought out businesses which were not associated with war. A further paradox is that although these industrialists were complicit in the iniquities of slave traffic and the savage regime of the plantations, they were also revered as social reformers. Figures such as Joseph Fry and Joseph Rowntree made enormous contributions to improving working conditions at home. The Cadbury brothers' model village of Bourneville offered social activities, holiday pay, education and pensions in exchange for abstinence and church-going.

Henry Tate, founder of the sugar empire, was a lavish philanthropist, endowing hospitals and libraries as well as the famous art gallery. Yet it is Tate and Lyle who have maintained a hold over the British sugar industry, which continues to be instrumental in ruthless protocols and trade agreements. Today, crippling European subsidies ensure that trade tariffs favour the production of sugar beet over cane, and the refineries in Europe over cane growers in desperately poor countries, in what Oxfam has described as "The Great Sugar Scam".

Sugar's appalling origins and the industry's continuing scandals are fuelled by an insatiable demand, particularly in the UK, where sugar spending is the highest in Europe and has been ever since it became available for mass consumption.

Sugar used to be an expensive rarity. Queen Elizabeth I loved bonbons, and aristocratic Tudor households would pride themselves on presenting elaborate sugar artifices, even making plates, dishes and bowls from sugar paste. Robert May, a professional cook who operated from the reign of Elizabeth I through to Charles II, specialized in extravagant confectionery sculptures - gilded sugar pies filled with live frogs and birds; a sugar stag that would bleed claret wine when an arrow was removed from its flank.

By the 19th century, though, plummeting prices meant sugar was no longer the exclusive luxury of the rich. New production techniques meant that boiled sweets became widely available for the first time. Laura Mason, in From Sugar-Plums to Sherbet, evokes the impact that they would have had on poor families in the 1860s. "Pears, during the few short weeks when they appeared in the greengrocers, were expensive, smelt delicious. . .but the sweet-stuff seller has a new line of bright red and yellow sugar drops. . .which produce a strong aroma reminiscent of pear, with the addition of a curious and intense sweetness which catches at the top of the nose...."

Once sugar had entered the diet of the poor it started to become a staple, alongside tea-drinking. In his 1930s exploration of northern working-class life, The Road to Wigan Pier, George Orwell observes how this diet persisted among the unemployed, despite its lack of nutritional value:

"When you are unemployed, which is to say when you are underfed, harassed, bored and miserable, you don't want to eat dull wholesome food. You want something a little bit 'tasty'...White bread-and-marge and sugared tea don't nourish you to any extent, but they are nicer than brown bread-and-dripping and cold water."

In Vera Drake, Mike Leigh's meticulous portrait of 1950s working class London, sweets are exchanged on the black market - affordable treats for the work-worn, bearing the faint echo of faraway fruits, nuts and spices.

But sweets were not just treats; they actually did you good. Aniseed balls originated as digestifs; humbugs developed from medieval cold cures; liquorice was thought good for coughs.

Once, sugar was part of the arsenal of the apothecary. Now it is reviled as a minor poison. Sugar rots your teeth, makes you fat, causes diabetes and heart disease. It's the newest gauge of how vigilant a parent you are. Let your child near a sweet and you have somehow failed in your duty.

I'll never forget the look of horror on my friend's face when we stumbled upon our small children playing 'cocaine dealers' with Sherbet Dibdabs. They'd laid out little lines of the white powder on a toy mirror. She didn't quite say it, but you could tell she was thinking: "It's all very well playing at Class A drugs, but how could you let them anywhere near sugar?"

A similar dilemma arose a few years ago when clubbing adolescents developed a craze for boiled sweet baby dummies which they would wear round their necks and intermittently suck to prevent Ecstasy-induced drying of the mouth and grinding of teeth. What were despairing liberal parents meant to advise, when their careful tolerance of pharmacological experimentation collided with their total ban on sugar?

This association of sweets with drugs is perfectly logical. Pharmacists have traditionally coated their prescriptions with sugar to make them more palatable. Those spoonfuls of sugar used to help all kinds of medicines go down, from herbal concoctions to neat opium. Now, it's sugar itself that is the addictive drug.

"KitKats, Jelly Babies, Maltesers, Krispy Kreme doughnuts... these were the designer Anya Hindmarch's drug of choice," warned the Sunday Times recently. Anya confesses: "'I had to have my fix...sugar was controlling my life.... I was relying on sugar to give me an energy rush but an hour or so later I would experience a crashing low and find myself craving another high.'"

Sugar also offers another flavour of sin: sex. We call each other sweetheart and honey, sugar and sweetie-pie. That most suggestive of music, the blues, is redolent with sweet sexual imagery; singers constantly invite sampling of their sugar pots and demand a little sugar for their bowls. Marilyn Monroe, in Some Like It Hot, is actually called Sugar - representing all that is seductive, irresistible and erotic. Even though, as she ruefully remarks, her fate is always to be on "the fuzzy end of the lollipop".

If sugar is the devil then its most ugly henchman must be sweets. Indeed, sweets in children's literature tend to be the source of temptations akin to the honey traps and candy men that prey on adults. Hansel and Gretel are lured to their downfall by an infant version of the House of the Rising Sun - the witch's candy cottage. Edmund in The Lion, the Witch and the Wardrobe is unable to resist the blandishments of the wicked queen who offers him the most delicious Turkish Delight in the world.

These images are overwhelmingly powerful because sweets - particularly certain categories of sweets - have become almost exclusively the province of children.

Maybe because it does contain some particles of nourishment, chocolate is still considered respectable fare for adults. But the more closely sweets resemble food the more they are disdained by children. They have their own lexicon of heady-scented concoctions like chews and gobstoppers, Flying Saucers and Black Jacks.

Richmal Crompton's William stories perfectly capture that fascination with exotic names and improbable colours and, best of all, the thrill of making a wise spending choice.

"They entered the shop and asked for Giant Humbugs and Golden Nuggets...changed their minds when the Golden Nuggets were on the scales and asked for Lime Lollies...changed their minds when the Lime Lollies were on the scales and asked for Treacle Dabs... and were summarily ejected by the exasperated shopkeeper while in the act of changing their minds yet again and demanding Pineapple Appetisers."

By another strange twist of fortune, sweets seem to be creeping up-market again with the recent flowering of twee shops on heritage high streets. But they are for adults rather than children, designed to indulge impossible longings to recreate the past.

You may feel nostalgic for the stab along the jaw at the first shot of an acid drop; the juicy succulence of a pastille; the explosion of sherbet on your tongue; the sheer hedonism of a gobstopper filling your cheeks. . . but these are the absolute sensory joys of childhood.

As our taste buds coarsen and simple ecstasies recede, adults can no longer savour the sensations of sucking and lip-smacking that define the infant condition.

No one knew better than Roald Dahl these seductive, wild pleasures, epitomised in The Giraffe and the Pelly and Me. The characters inherit their own sweetshop, with delicacies from all over the world.

"There were Gumtwizzlers and Fizzwinkles from China, Frothblowers and Spitsizzlers from Africa, Tummytickers and Gobwangles from the Fiji Islands and Liplickers and Plushnuggets from the Land of the Midnight Sun. . . there were Nishnobblers and Gumglotters and Blue Bubblers and sherbet Slurpers and Tongue Rakers, and as well as all this, there was a whole lot of splendid stuff from the great Wonka Factory itself, for example the famous Willy Wonka Rainbow Drops - suck them and you can spit in seven different colours. And his Stickjaw for talkative parents. And his Mint Jujubs that will give the boy next door green teeth for a month."

Dahl's dazzling confectionery defines the whole domain of childhood: the disgusting habits, the otherness, that magical, suspended state of surrealism.

There has always been a strong thread of the surreal in the alchemy of sweet-making. Seaside novelties like rock bacon and eggs and candied false teeth date back to earlier sugar sculptures of gloves and slippers, knives and knots, snails and snakes. In Mexico, the Day of the Dead is celebrated with sugar models of skulls, coffins, skeletons, bones and tombstones. In Sicily, they make sugar models of ballerinas, cowboys, Disney figures.

Even the names of real sweets border on the surreal. Tim Richardson, in Sweets: The History of Temptation, revels in the sounds of forgotten treasures like the Tootsie Roll, Milk Duds, Black Bullets, Zagnuts, Rainbow Crystals, as well as bizarre commemorative items like Gibraltar Rock, Wellington's Pillars, Bonaparte Ribs and Nelson's Balls. Contemporary favourites, according to a cross-section of thriving internet sweet suppliers, include Cherry Lips, Candy Letters, Freaky Fish, Jelly Pythons, Sweet Tobacco and Fizzie Wizzies.

Extravagant names, colourful excess, intoxicating variety - sweets are a model of human inventiveness and exuberance. That's why we should throw off the shackles of religion, repression and joyless disapproval, confiscate the candy from the kids and reclaim it for humanism. What we need now is our own litany of indulgence: silver cant-stoppers to offer to Jehovah's Witnesses at the door; green evolutionary lizards to pass round outside creationist schools; God is Dead comfits and flying pigs with angel wings. Let's glory in our own jelly Popes - to devour head first; our Secular Sizzlers, Rationalist Rock, Enlightenment Mints, Marx Mallows, Freudian Fizzies, Darwin's Delights and AgnoSticks.

And maybe a few acid drops to cool that mounting election fever. Served with a large bag of humbugs.