The clock is renowned for its accuracy and even survived a dozen attacks by Luftwaffe bombers during the Second World War, continuing to mark the time within one and a half seconds of GMT. It has, however been late on occasion. In 1962 snow accumulation caused the clock to ring in the new year ten minutes late and in 1976 the clock stopped when a piece of its machinery broke. It also ground to a halt on April 30, 1997, just 24 hours before the general election and once more three weeks later. Big Ben is the name of the clock's 13-tonne bell, which was named after Sir Benjamin Hall, the British Commissioner of Works at the time of the clock's construction. The official name for the Gothic tower in which Big Ben nestles is St Stephen's Tower. Standing 100 metres (315ft) tall it was completed in 1858, after an 1834 fire destroyed most of the Palace of Westminster.