If you like periods of abstinence in your consumer heaven, you may wonder at this need to launch Easter so early. A Safeway spokesperson said the supermarket chain responds to customer demand. "We are all busy people; our customers may want to buy Easter eggs as part of their normal shop."
But Judy Fenn, a shopper emerging from the Reading branch of Safeway, did not agree. "I haven't taken my holly down yet," she protested.
Mars Confectionery sides with the supermarkets. The company contends that since we buy pounds 330m-worth of confectionery during Valentine's Day, Mother's Day and Easter Sunday, it helps to be able to spread our shopping, physically and financially.
This theory lacks plausibility. Say you buy eggs 10 weeks early. No, darlings, they're not for eating yet. You put them in the hiding place that failed you at Christmas. The eggs disappear but the children reassure you: there are still nine weeks to buy them again. Next time you put them in the garage. The week before Easter you go out there and find the eggs sitting in a pool of leaked paraffin. You throw them out and start again. This time you arrive at the eggs section to see Easter sold out.
The reality is that almost all eggs are bought at the last minute. Richard Frost, Cadbury's head of public relations, says: "Easter doesn't have the same dynamics as Christmas. It's a one-product occasion, with 80 per cent of eggs bought just before Easter Sunday."
So why do supermarkets take up valuable shelf space with a product they know isn't going to sell for weeks? And why is Easter on the shelves as the same time as Valentine's Day and Mother's Day, both of which fall before it?
Two theories emerge. Mintel, the market research company, finds that Easter helps consumers to come out of their post-Christmas hibernation. The earlier this swing occurs, the better.
Robert East, professor of consumer behaviour at Kingston Business School in Surrey, agrees that holidays such as Easter have a powerful control over spending. "The associations of Easter are all pleasant," he says. "Eggs could be part of giving the store a nicer feel, in the same way that the smell of freshly baked bread makes it more attractive."
Mintel's research supports the second theory, put forward by an independent grocer who did not want to be named. Supermarkets know that food sales plummet after Christmas; eggs help to fill the shelves, and don't have to be paid for until after Easter. In fact, a confectionery buyer described to Mintel how he has to fight off confectionery salesmen, who see the supermarkets as stock-holders for their product.
By extending the selling period for Easter eggs, supermarkets give the manufacturers an advantage over other confectionery and gift lines, and strengthen their own hand when negotiating a deal. Neil Mason, of Mintel, says, "The margins on Easter eggs are higher than on other chocolate products. Shoppers may trade up, and spend more on eggs than if they were buying boxed chocolates, for example."
Consumers are certainly vulnerable to manipulation. Three out of four shoppers enter the supermarket without a shopping list. Jeff Harris, of the research company Harris International, describes them as arriving semi-comatose. But he adds: "Supermarkets fail to sell to their customers all the things they could have, partly because they clutter the shelves with things like Easter eggs when no one is buying them."
Supermarkets, however, are careful with their shelf space. Efficient Consumer Response (ECR) is the latest American formula which helps supermarkets to have as little product as possible at any one time in their supply chains. They order stock in small amounts, not once a week, but daily. For some products, supermarkets are proposing twice-, even thrice-daily deliveries. One wonders whether shelf fillers will start to outnumber customers.
At home, ECR would mean one pint from the milkman in the morning. A request for rice pudding would trigger sending someone out for another pint. Only when football is rained off and your son arrives home with half the team do you buy six pints from the supermarket. Will the family notice you've been making efficient consumer responses all day? Will they care? But at least you won't have wasted any milk.
With so much detail in the life of a supermarket, managements risk information overload. And this is before they begin analysing the data spewing out from the 20 million spy cards held by customers using loyalty schemes. By possessing the exact measurements of all your shoppers you understand their every need - with the exception of when they want to buy Easter eggs.
The purpose here is to respond to our need to be cheered up, rather than our need to buy. In this scenario, supermarket shelves leave nothing to chance by putting a little of everything on the shelves. Of course, you can always derail the information-obsessed supermarket manager. Next time you fill in an application form for a spy card, do as my menopausal, childless friends do. Say you are married, aged 21, with four children. Then watch nappies eclipse the Easter displays.