Arwel Jones from the National Library of Wales told ITV News that he is hoping that the damage will be limited - "the most valuable stuff is housed in purpose-built cells at the very bottom of the library, and this fire is at the very top."
He admitted to concern that the damage from water pumped onto the building by firefighters would be as bad as the fire damage.
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A new vaccination programme starts today protecting young children against MenB disease, which can cause meningitis and septicaemia.
Rather cloudy at times, but with some sunny intervals likely too.
Andrea Byrne presents the first episode of the new series Helimeds which follows the Welsh flying medics.