An image of Boris Johnson dressed as Orville the duck has been projected on to the side of Cardiff Castle by the Led By Donkeys campaigners.
The image was accompanied by the words “Lame duck… Totally useless prime minister.”
It is a reference to Johnson’s accusation that Labour leader Jeremy Corbyn is a “giant chlorinated chicken”.
The Conservatives have been accused of “silly playground behaviour” by members of their own party after they launched a campaign depicting Corbyn as a chicken.
On Friday afternoon, the Conservatives’ Twitter account shared a doctored image of Corbyn in a chicken suit, with the caption: “Hey (KFC), we’ve found an even bigger chicken than you.
A video of the prime minister has also been cast on to the side of the Titanic Museum in Belfast.
In the video, a clip of Johnson saying “Brexit means Brexit and we are going to make a titanic success of it” is contrasted with news clips from the last week, and footage of the Titanic sinking.
The anti-Brexit campaign group also projected a clip of Michael Gove on to the side of Cardiff Castle, in which he makes a speech about the effects of a no-deal Brexit on the farming industry.
Earlier this week, after a picture of Jacob Rees-Mogg showing little regard for the House of Commons business went viral, they projected the image on to the side of Edinburgh Castle, with the words “Lying Tory”.