They're not Terry's - they're not even Dawn's, these Chocolate Oranges are the property of ecstatic shoppers who have taken advantage of a glitch at Tesco.
A computer error at the tills enabled surprised customers to pick up the popular treat for just 29p each - a tenth of their value.
Some shoppers filled their trolleys with the chocolates - advertised on TV by comedian Dawn French - and cleared entire stocks.
One temporarily forgot his waistline by buying 192 of the products, which normally retail for £2.75, for just £57 - saving a staggering £471.
The error is believed to have affected all main Tesco 'Extra' supermarkets as well as their Metro stores - around 1,250 in all - but not the smaller Express outlets.
A spokesman would not say how many oranges were sold or how much it had cost the company.
Within hours, a Facebook page called 'Terrys Chocolate orange glitch, I was there' was set up and flooded with people posting photos of their chocolate hordes as well as their receipts.
Within hours of the glitch being posted on a money-saving website, 57 pages of comments had been posted from excited shoppers.
Reports were posted of people visiting five different stores after clearing each shops' shelves to make the most of the deal.
They even put up photos of pyramids they had made from the chocolate boxes.
One lucky shopper made a giant rabbit out of their oranges.
Other people uploaded photos using the treats to spell out the word TESCO and YAY.
Shoppers were able to combine a three-for-£5 deal on the chocolate with another buy-one-get-one-free-offer.
However, a glitch meant the tills applied a further discount when the chocolates were bought in multiples of six.
That meant the chocolate, which usually sells for £2.75, was being sold for 10 per cent of the original price.
Within minutes, people posted photos of their receipts - the first showed £8.95 being spent just on chocolate oranges, with £73.15 being saved.
It wasn't long before the page soared in popularity, hitting a staggering 3,426 degrees on the website's 'temperature gauge'.
The Facebook page has 307 'likes' and features hilarious photos of creations people have made with their chocolate orange boxes.
Photos were posted showing a figure of a man and giant pyramids built entirely from oranges.
They posted comments like: 'Just bought 42 for less than £13! Bought six to test the glitch, then bought all the rest they had! :)'
Another said: 'I only bought 42 as that's all they had on the shelves. I wish I asked for more, but then I'd be worried I would be banned having bought all their stock!'
Vadim Baines-Jones, who bought 192 chocolates, posted a picture and wrote: 'Our little stash to join in the fun. Sorry it's an untidy pyramid. 192 there, and a 'few' shipped off to friends not in photo.'
Another made fun of the chocolate company's slogan by writing: 'They're not Terry's, they're mine... thanks Tesco.'
It is believed the glitch affected Tesco Extra and Metro stores across the country, but not the Express outlets. It has around 2,500 stores in total.
A spokeswomman for Tesco said the error only lasted 'a couple of hours'. She said: 'We deal with 35,000-40,000 products, so sometimes these things happen. We have made lots of people very happy.'
She would not disclose the cause of the glitch or how many Chocolates Oranges were sold on the deal, but added: 'We are putting steps in place to make sure that it does not happen again.'
Kraft Foods, which makes Terry's Chocolate Oranges, were unavailable for comment.
The glitch comes just months after a similar blunder at the supermarket after its high profile Price Check regime was hijacked by savvy shoppers.
Tesco was so confident about its low prices that the Price Check regime promised to refund 'Double the Difference' where a basket of groceries was cheaper at the rival.
The scheme proved to be hugely popular with hard-pressed shoppers who found ways to take maximum advantage of the deal.
They identified a range of products which were significantly cheaper at Asda under short-term promotions and shared the details across a raft of internet money forums.
In some cases, shoppers were claiming hundreds of pounds a week in refund shopping vouchers from Tesco.
Tesco initially responded by capping the value of refunds to £20 a week in what was seen as a major blow to its price-cutting credentials. However, it then went even further and scrapped the promise to offer refunds of 'Double the Difference'.
A number of other companies have cancelled promotions after relaising that they were overly-generous.
Crisps makers Walkers started a month-long promotion that rewarded customers with £10 prizes if they could predict where and when it would rain.
But there was so much rain that the company paid out a staggering £600,000 in just two weeks and faced an overall bill of more than £1million.
Eighteen years ago a ‘free flights’ offer by Hoover almost ruined the firm, turning into a £50million fiasco after so many took advantage.
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