Kony 2012 is an unlikely internet phenomenon. The 30-minute documentary about a despot Ugandan warlord has been watched more than 30m times online in less than 48 hours.

The hard-hitting film, uploaded by a group seeking to expose the guerilla leader Joseph Rao Kony, was relatively undiscovered until two days ago despite being first watched on the website Vimeo last Friday.

In the past 48 hours, Kony 2012 has been viewed more than 21m times on YouTube and 11m times on Vimeo.

According to YouTube statistics, the Kony video is most popular with young women aged 13 to 17 and men aged 18 to 24.