Members of Greenpeace used safety shut-down buttons to cut off power to the assembly line before handcuffing and chaining themselves to unfinished vehicles.
Land Rover parent company Ford asked police to move in and arrest the protesters after six hours of negotiations.
Stephen Tindale, Greenpeace executive director, was among the protesters who were arrested: “We want to make the point that these off-road vehicles are totally out of place in an urban setting.
“The company claim to care about the environment but are doing everything they can to prevent fuel efficiency.”
Ford will be spending £3m a year on advertising in London, but claimed most of its vehicles will be exported to be used on rough terrain.
Land Rover said protesters’ claims about fuel consumption were misleading and that the average fuel consumption of the models produced at the plant was around 30 miles per gallon.
The Transport and General Workers Union criticised the protest. Gerard Coyne, TGWU regional secretary, says: “Greenpeace’s actions are insensitive and potentially dangerous. They ought to think about the consequences of hitting production at a difficult time for the industry and for the people of the West Midlands, who have recently seen the closure of Jaguar’s Browns Lane plant and the mass redundancies at MG Rover.”
Land Rover said it was hard to estimate exact damage the protest had caused. The Range Rover line produces an average of 9 vehicles an hour, costing an around £50,000. A spokesman said that production continued during the protest in other section of the plant and the no physical damage had been done.
Land Rover will be reviewing its security.