Emergency roof repairs were carried out across four galleries at the British Museum last week following an "endless series of leaks", according to a report in Arts Newspaper.
The action was taken in galleries containing Greek, Cypriot and Japanese artworks, where buckets were being used to catch drips and extra heaters to reduce humidity levels.
In a speech last year, museum Chair George Osborne acknowledged issues with the museum's fabric: "For decades, it has been patched up in a piecemeal way and by closing galleries when the rain comes in."
Plans to upgrade the entire building, starting with galleries on the ground floor, are in place. However, progress was impacted by the resignation of director Hartwig Fischer following the revelation last year that over 2,000 artefacts had been lost, stolen or damaged over a 19-year period.
Last December, the British Museum signed a 10-year partnership with oil giant BP to fund a significant redevelopment of its Bloomsbury premises in a move that environmental groups have heavily criticised.
The museum said the £50m from BP will help it deliver its master plan and ensure millions of visitors can "continue to access the collection for generations to come".
In a statement to Arts Newspaper, a museum spokesperson said: "We have been open about the fact it is in need of full-scale renovation." They added that the museum's master plan represents "one of the most significant cultural redevelopment projects undertaken anywhere in the world."