Costa has denied making customers pay an extra 30p for large caffe lattes despite being served the same quantity as a regular latte.
A Facebook video has garnered over 11 million views showing a large latte seemingly fitting perfectly into a regular cup.
The video’s creator, builder Paul Hopkinson wrote alongside: “There you go country of England, the regular and the large are indeed exactly the same size.
“Whoops Costa. Oh dear.”
In response to his accusation, Costa stated there is a four fluid ounce difference between the two sizes, adding that neither cups are filled to the brim for safety reasons.
Costa wrote on Facebook: “Hi Paul, thanks for taking the time to send in your video! Despite what it looks like I can assure you you’re not being duped in any way.
“The regular cup is a 12oz and the large is a 16oz so there is 4 fluid oz in size difference. Plus you also get the extra shot of coffee, hence the price difference!”
The company added: “Also for safety reasons there is no way we would be able to fill the cup that high as it would end up burning someone.”