Marks and Spencer has admitted a massive bloomer and backtracked on a redesign of its beloved 'granny pants' - after a backlash from angry customers.
The retail giant made a few minor alterations on its best-selling five pack of ladies cotton briefs, including moving the seam from the front, to the side. It will be moved back to the front later this year.
But shoppers including many who have bought the pants for years were furious and posted angry reviews.
Buyers complained the altered knickers - sold under the same name - were SMALLER at the sides and less comfy thanks to seam adjustments.
The M&S website features reviews from loyal shoppers complaining the redesign was a "downgrade" and the "fit was not as good".
Reviewers who had bought the pants for years begged the retail chain to ditch the new design and bring back their "old much loved knickers".
And after a BBC radio consumer affairs programme featured a plea from one disgruntled customer, M&S bosses promised to ditch the new design and bring back the old undies.
One review said: "They were perfect fit before and so comfortable! Please could M&S go back to the seam and the front!
"I think it would make some happy customers as quite a few of us are rather disappointed with the new version."
Another added: "Old version was great, these are awful.
"The old version with the front seams was very comfortable, however this version now has seams at the side which make the fit much worse.
"Bought several packs as I expected them to be like the old ones and I will be returning all unopened packs.
"I agree with many other reviewers, please go back to the old front seam version, they are were great."
One wrote: "Were my fav knick before changed seam.
"Front seams have been changed to have side seams, therefore these knickers are not as structured at the front. Please change back."
The popular M&S Collection five pack of Supima Cotton & Modal No VPL pants come in a 'full brief' and 'high leg' design and cost £12 in black, or white and nude.
Judging by the change in usually-sparkling reviews from devoted buyers, the design was changed in around April last year.
It is understood the flat seams on the front of the pants were scrapped and replaced with more typical raised ones on the sides.
Shoppers also claim the overall size of the pants was increased, but the material over the hip was made smaller.
The photograph on the website initially remained the same - as did the product code for the pants - prompting shoppers to unknowingly buy the altered design.
Negative reviews were left online throughout last year without avail, until one loyal pants-buyer contacted BBC Radio 4 programme You and Yours.
In an interview broadcast on Friday, shopper Dinah Barry told the programme : "They were just extremely comfortable and I know form reviews that lots of other women felt the same.
"[On the new design] the seam arrangement had changed so that they were raised seams at the sides as most knickers are. They were also cut so that the side of the knickers was a lot smaller.
"They were very different. The thing they had in common was the fabroc, and the fact that they were knickers, but not much else."
Bosses responded by looking at reviews and speaking to suppliers, before promising to bring back the old knickers later this year.
They also gave Dinah a bespoke run of six knickers in the old style.
A spokeswoman said: ""Our loyal customers are very important to us. We looked into this and decided to change the knickers back to the original style lines following her valuable feedback.
"As a gesture of goodwill we are making the customer some in her size until we can get them into stores again.
"We really appreciate the customer taking the time to contact us."
M&S said it has 27.6% of the UK lingerie market and more than one in four women buy from the store, with them selling two pairs of knickers a second every day.
As news hit that the high street giant will revert to the old design again, many customers praised M&S.
@LucozadeEnergy you see even M&S listen to their customers - changing their big knickers back to the old pattern after complaints! They know the customer is ALWAYS right. Whereas you are just being BIG PANTS. Bring back the REAL Lucozade x
— sarah baker (@lairf1) March 1, 2018
— Louisa Osmond (@Louisa_Osmond) February 28, 2018