LEAVING your precious baby in daycare is heart-wrenching enough – but one mum got the shock of her life when she caught the childminder BREASTFEEDNG her daughter.

The adoptive mum, who can’t lactate, had been bottle-feeding her child and had left formula milk with the carer.

In a letter published in Dear Prudie, an advice column on Slate, the anonymous American mum said she had thought the minder was “amazing” even though she had initially shamed her over the use of formula.

She wrote: “I am a single mother of an adopted baby, and I am opting to formula-feed since I can’t lactate.

“I am a working mum as well, and found a home day care provider who seemed amazing —she has two kids of her own (one a little older than my daughter) and has run this home day care for five years or so.

“The only bump in the road was on the first day when I pulled out the formula and bottles, and she wrinkled her nose and said, “You feed her that slop?” I ignored the barb (I’m used to it), gave a quick rundown, and went on my way.

A few months later, the mum turned up early and walked into the daycare centre through a side door.

An assistant tried to stall her but she brushed past.

She wrote: “When I got to the area of the house where my daughter was, I about fell over. The day care provider was NURSING MY BABY!”

Amazingly, the woman told her she should be thanking her for the act.

She wrote: “I marched over, took the baby from her arms, and asked her if she was crazy.

“The provider said that she was saving my baby from chemicals I was trying to force into her body and I should thank her for doing it all these months!

“I didn’t say anything; I just grabbed the diaper bag and got the hell out of there.”

Advice columnist Daniel Mallory Ortberg was shocked by this clear violation –advising the mother to report the incident to the police.

He said: “Oh my GOD. That is my first thought, is just: Oh, my GOD. If this isn’t worth reporting her to a supervising agency, I don’t know what is.

“This is a huge breach of trust, a total violation, and absolutely worth reporting.”

Other mums took to social media to express their disgust over the carer’s actions.

One wrote: “Ew! I don’t care what you choose to do, formula or breast feed, but what you won’t get to do is choose for someone else.”

Another added: “What she did was wrong on so many levels.”

A third said: “Report her and the day care provider if separate. Find a new place. That is creepy.”