Animal Rebellion protesters have poured milk on to shop floors, displays and products across the country, including Harrods.
The group co-ordinated the action in stores like Waitrose, Whole Foods and Marks and Spencer in London, Manchester, Norwich and Edinburgh just before 12pm on Saturday.
Video footage reveals that the protestors poured milk, taken from the shelves, on to display cabinets in Harrods' food hall in Knightsbridge.
More footage showed another group emptying milk bottles on to the floor and across a table laden with cheeses in Fortnum and Mason in Piccadilly.
Animal Rebellion said it is calling for a plant-based future and highlighting the need to support farmers in transitioning to a sustainable plant-based food system.
Lou Hadden, a charity worker from Hertfordshire, who joined the action at Fortnum and Mason, said: "This is not how I imagined spending my weekend.
"Unfortunately, this disruption is necessary to get those in power to listen to the academics at Oxford, Harvard and the IPCC (Intergovernmental Panel on Climate Change).
"The world's best climate and land scientists are calling for the transition to a plant-based food system.
"We need bold and decisive politics at this time, not the horror show we currently see."
Meanwhile, Skylar Sharples, an international development graduate from Bristol and one of the protesters at Harrods, said: "Supporters of Animal Rebellion are back acting because (Prime Minister) Liz Truss and Ranil Jayawardena (Secretary of State for Environment, Food and Rural Affairs) are again deciding to ignore calls to start building a better future.
"A plant-based future would see a beautiful world for us all, thriving with nature and life.
"The steps to properly support farmers in this transition need to begin now."
Last month, vegan activists superglued themselves to the top of empty lorries outside a Muller dairy and sprayed white paint on the walls of Parliament.
At around 5am yesterday 40 Animal Rebellion eco-warriors clambered on top of HGVs as part of a blockade of the milk factory’s depot in Droitwich, Worcestershire.
Campaigners leapt onto the lorries and slashed their tyres, causing chaos for motorists trying to access the large industrial estate.
The move was followed by demonstrators spraying white paint using fire extinguishers beneath the Elizabeth Tower, as well as throwing more paint from four litre milk cartons on the road, causing traffic to come to a standstill.
