Dad left red-faced after sending son to school in crude Christmas jumper

At first glance it's not immediately obvious what's wrong with this Christmas knit, but it soon becomes apparent

The photo was posted by AngryHamzter, who identified himself as the boy's father (AngryHamzter/Reddit)

A father who sent his five-year-old son to school in a festive jumper had a nasty surprise when a teacher pointed out the design featured Father Christmas urinating the words 'Merry Christmas'.

Judging from the picture, posted on Reddit via Imgur, it was an easy mistake to make as Father Christmas' bad behaviour is not immediately obvious at a glance.

Accidentally sent my son to school wearing his newly bought sweater. Didn't realize what Santa was doing until his kindergarten teacher pointed it out to me when I picked him up.

The photo was posted by AngryHamzter, who identified himself as the boy's father.

He captioned the image: "Accidentally sent my son to school with his newly bought ugly Christmas sweater.

"Didn't realize what Santa was doing until his kindergarten teacher pointed it out when I picked him up after school."

The post has attracted a good deal of attention, attracting more than 640 comments on Reddit.

"Urine trouble now," quipped one commenter.