199 pieces damaged during past three years at national museums LONDON, Nov. 5 (UPI) -- British officials said 199 art exhibits have been lost or stolen from Britain's national galleries and museums during the last three years. The figures, released under the Freedom of Information Act, revealed many of the artworks, including pieces by Poussin to Roy Lichtenstein, were damaged by the very staff members who are supposed to protect and preserve them, The Daily Telegraph reported Monday. One of the incidents detailed in the Freedom of Information Act release revealed a James Francis Mauber portrait of 17th century poet John Dryden had an ornament knocked off its frame when a member of a tour group was knocked off balance by a security guard at the National Portrait Gallery. Another incident involved a 17th century Edward East night clock at the British Museum being broken when a visitor tripped and a Japanese clock was damaged when a cleaner fell into it during a power outage. The glass covering a photograph of Margaret Thatcher, taken by Helmut Newton, was cracked when a staff member fell as the frame was being lifted to be packed for loan and the artwork hit the ground. "Britain's museums and galleries are rightly renowned around the world for the quality of their collections and for their curatorial and conservation standards," said a spokesman for the Department for Culture, Media and Sport. "Inevitably, however, with so many items being transported, conserved, catalogued and displayed at any one time, a small number will from time to time get damaged," the spokesman said. We are confident though that the highest standards are maintained and that accidental damage to items is not a significant cause for concern.