When your mother-in-law betrays your trust in the most disrespectful way.

If your mother-in-law gave your child a drastic haircut, without asking your permission, would you be angry?

A mother, from the UK, has been left fuming after her (now ex) mother-in-law did just that.

The Mumsnet user asked commenters if she was overreacting after her ex-husband’s mother made the decision for her granddaughter and chopped “all” the six-year-old’s long hair off.

“It’s gone from being long, blonde, beautiful waves to a shoulder length bob,” the mother posted online.

She was also annoyed that the haircut included a new fringe.

Podcast: Why are parents so stressed? (Post continues below)…

“I am beyond angry,” said the mum, explaining her six-year-old daughter “hates” her new hairstyle.

“I’ve had no explanation from [my mother-in-law] or [ex-husband] who both appear to think I am overreacting.”

Her post has attracted more than 500 comments, sparking debate with other parents.

“It’s both parents’ decision to cut long hair short,” said one.

Other commenters said the grandparent had “crossed the line”.

“She told me this morning she was in tears as soon as it was done and was told to stop crying as she’s a big girl now…

“She wore a hat all day in school yesterday apparently as she was so upset,” said the mum.

One Mumsnet user suggested the six-year-old should go to a “decent hair dresser” and get it cut “really nicely”.

“Then it will grow out beautifully and be long again if that is what she wants.  It is horrible growing out a fringe you didn’t want,” the commenter added.

How would you feel if your mother in law did this to your child?