Hacker group Anonymous' @AnonCircle has announced a "Loot and Riot Day" on 1 May with a tweeted image of David Cameron running away with a supermarket trolley full of stolen goods, over the slogan "Rob the rich before they rob you", doing the rounds.
An earlier Anonymous group tweet linked to an image of lasers and dinosaurs in a cyberwar theme also highlighted the 1 May date.
There has been no formal confirmation by the group on its May Day plans. No other details were available.
May Day is the traditional date for radical protests and worker celebrations around the world.