Members of the museum's workers' committee interrupted the opening ceremonies this week by whistling and banging drums, and brandishing banners and stickers saying "Save the Prado". They plan a series of protest actions including strikes - although their leader, Antonio Solano, reckons a work- to-rule would be sufficient to bring the museum, housing one of the world's finest art collections, to a standstill.
More than 100 sixteenth and seventeenth century paintings, including four splendid Caravaggios as well as works by Titian and Breughel, celebrate the pleasures of the five senses. Workers say the exhibition, "improvised at the last minute", was mounted with unprecedented haste, causing disruption throughout the museum. They say the accumulation of temporary displays and major repairs to the dilapidated building will close dozens of rooms.
"For weeks visitors have been tripping over ladders and toolboxes, as workers have been driven to the limit, shouting to each other, banging, causing disruption that is totally inappropriate in the Prado," complained Alfredo Pineiro, a member of the workers' committee and a museum restorer.
Workers who have seen their numbers cut and wages frozen are "totally demoralised", Mr Pineiro says. They want some order to be put into the shambolic internal organisation of the flagship of Spanish culture.
It was, workers say, "madness" to mount such an ambitious project during major structural repairs.
A spokesman for the sponsoring bank, the BBV, said the exhibition had not figured in its plans for this year but was the result of an invitation by the Secretary of State for Culture, Miguel Angel Cortes.