Coca-Cola were forced to issue an apology to a Canadian family this week after a member found an insulting message underneath a drinks cap belonging to the company.

The Loates were out for a family meal, when Blake unscrewed the cap on her Vitamin Water Zero to read the words, ‘You Retard’. 

"We immediately thought 'You have got to be kidding me,'" Blake told the Alberta Huffington Post.

"We thought it might have been a disgruntled employee or someone in a (bottling) plant playing a joke."

Blake showed her father, Doug, the cap and he was equally appalled.

Doug’s younger daughter, Fiona, has cerebral palsy and autism, which spurred than man to stay up all night writing a letter to the company.

"You see,the "R" word is considered a swear word in our family. We don't use it. We don't tolerate others using it around us. We ARE over-sensitive but you would be too if you had Fiona for a daughter!" she said. 

Doug's powerful letter to the company, which has since gone viral.

The family was contacted the next day after Coke received Doug’s letter to explain that the cap was part of a Vitamin Water competition, where one random English word is paired with a French word and printed on every individual cap.

'Retard' in French translates to late.

Shannon Denny, director of brand communications for Coca-Cola Refreshment Canada, told the Metro Calgary, “We are certainly very apologetic for this oversight.”

“We didn’t mean to offend at all."

Blake added, "we're just really glad we're getting a chance to let people know how hurtful the 'r-word' is."