Online marketplace Vinted says it has removed sexually explicit adverts, after a mum reported seeing a video depicting what she believed to be a pornographic scene while browsing for clothes.
Kirsty Hopley, 44, from Carlisle, said she was searching the app for a dressing gown when the ad popped up.
She was sitting next to her teenage daughter at the time.
Ms Hopley reported the content to Vinted and later contacted Ofcom.
She told BBC News the video, which started playing automatically, showed a "sickening" graphic and violent sexual encounter.
