This woman’s selfie taken at the Notting Hill Carnival has been shared thousands of times after she said she was punched in the face for telling a man to stop repeatedly groping her.

In a Facebook post which exposes the darker side of the annual street party “supposed to be about community and good vibes”, Mary Brandon said she spent nine hours at hospital receiving treatment following the alleged assault.

Ms Brandon encouraged others to raise awareness of her image and “get the word out that this isn’t OK”. Since being uploaded yesterday it has been shared more than 5,000 times.

Describing the incident at the celebrations on Monday, Ms Brandon said: “A man in the crowd grabbed my arse. When I told him not to he did it again.

“I pushed him away, exercising my right to tell a man to stop touching my body without my permission, so he took a swing at me and punched me in the face.”

A police investigation into the incident is now underway, the Evening Standard reported, and Ms Brandon’s message has encouraged other women to come forward with their own stories of sexual abuse at the event.

Before and after: Mary Brandon's Facebook profile picture (left), and the image taken after she was hit (Mary Brandon/Facebook)

Another Facebook user, Hannah Dart, responded: “On my way home from carnival an amazing woman told me she'd had a broken bottle held up to her face when she'd yelled at a man for grabbing her friends boobs.

“I am so angry that these men take space and freedoms away from us to feed their own pathetic egos. Keep standing up for yourself, you did an amazing job.”

Ms Brandon said some of her friends had suggested it might be “best not to do anything at all” when presented with a similar situation.

Video: Crime at Notting Hill Carnival 2014

But she said anyone who thinks it is “OK to treat women like this” should stay away from the carnival in future, adding: “I can honestly say I will always stand up to someone who thinks they can get away with this behaviour.