Facebook has apologised after it deleted a page showing two little girls pretending to breastfeed their dolls.

Express Yourself Mums – an NHS-backed breastfeeding website – discovered its group had been removed on Friday for a "policy violation".

The previous day co-owner Sharon Blackstone had posted a picture of her seven-year-old daughter Maya playing with her doll.

Blackstone, from North London, said: "After giving her doll a naming ceremony, Maya told me that her baby needed to be fed. As she's only ever seen me breastfeed her little sister, it was the most natural thing in the world for her to pretend to do it the same way.

"Like many mums, I got out my phone and took a picture because I thought it was a sweet moment. I shared it with the 600 other mothers on our Facebook page because I thought it was something they'd like to see. After all, don't millions of people post cute pictures of their kids on Facebook?

"A few minutes later, my business partner Carly Silver also posted a similar shot of her seven-year-old daughter Izzy cradling her baby doll in her arms.

"Afterwards, about 15 mums posted messages saying they loved them. Only one mum said she didn't like them because they might be seen by questionable people."

Last Friday afternoon Express Yourself Mums discovered the page – which has more than 600 fans – had been removed. The reason given was "a policy violation", which can include nudity or obscenity.

Under pressure to reinstate the page from more than 400 women who formed a campaigning group, Facebook has now apologised for "the error" and reinstated the page.

Blackstone said: "How can little girls playing with dolls cause so much offence? There wouldn't have been the same problem if she had been pushing a pram or, ironically enough, feeding her doll with a plastic bottle."

Facebook has a history of categorising photos of breastfeeding as "obscene content" and removing them. But this is the first time a British group – or a picture of children role-playing breastfeeding – has been taken down.

A row in 2008 caused the site to be flooded with pictures of breastfeeding mothers and led to demonstrations outside the company's Palo Alto HQ.

Last year Facebook also deleted a page for The Leaky Boob, a US online support group, for "violating its terms of service". It was later reinstated.

This December American mother Heather Stultz was told a picture of her baby breastfeeding violated pornographic content rules when she posted it on a page called Respect the Breast.

In the past Facebook has said that photos where a nipple or areola can be seen are against its policy. It has since said it usually removes breastfeeding pictures only when they are brought to its attention by other users who lodge complaints.

Facebook says any complaint is reviewed by its operation team, which then makes the decision about whether to remove the images or close down the group.

A Facebook spokesman said: "The group was removed in error. It will be reinstated, and we apologise for any inconvenience caused."