The clock in the clock tower of the Houses of Parliament is one of the most recognizable of London’s landmarks. The clock and the clock tower are commonly and inaccurately referred to as Big Ben. Big Ben is actually just the name of the clock’s largest bell and not the clock itself nor the tower.
When the clock was first built over 150 years ago, it was designed to be one of the most accurate clocks in the world - accurate to one second on the first strike of the hour. The clock was installed in and started working on the 31 May 1859. Although, famed for its reliability, the clock has had its share of malfunctions, breakdowns and other interuptions in operation over the years.
1916 For two years during World War I, the bells were silenced and the clock faces were dark at night to avoid German Zepplin attacks.
1939 During the Blitz, the clock faces were dark at night to avoid to guiding bomber pilots. The bells, however, continued to ring.
1941 The clock stopped at 10.13pm on 3 June and remained stopped until 10.13am the following morning, after a workman repairing air raid damage to the clock face dropped a hammer into the works.
1949 The clock slowed by four and a half minutes. This was caused by a flock of starlings landing on the minute hand.
1962 On New Year’s Eve, the clock slowed due to heavy snow and ice on the hands. This caused the pendulum to detach from the clockwork, as it is designed to do to avoid serious damage elsewhere in the clock’s mechanism. Thus the New Year was chimed in ten minutes late.
1965 On 30 January, the bells were silenced for Winston Churchill’s funeral.
1976 On 5 August, the clock suffered its first and only major breakdown. The air brake speed regulator of the chiming mechanism broke due to torsional fatigue causing one of the clock’s fully wound weights to spin the winding drum out of the movement. The clock was severely damaged. It was shut down for a total of twenty-six days over the next nine months and was finally reactivated on 9 May 1977
1997 The clock stopped on 30 April, just twenty-four hours before the general election, and then stopped again three weeks later.
2005 The clock stopped at 10.07pm on 27 May, possibly because of unseasonably hot weather. The temperatures in London that day reached over 31°C. The clock started again but then stopped again at 10.20pm and remained still for about ninety minutes before resuming.
2005 On 29 October the clock was stopped for thirty-three hours for maintenance.
2006 On 5 June, the clock tower's quarter bells were taken out of commission for four weeks so that a bearing holding one of the quarter bells could be repaired. During this period, BBC Radio 4 broadcast recordings of British bird song followed by the pips in place of the usual chimes.
2007 On 11 August, the clock was stopped again so that the bearings in the clock's chime train and the great bell striker were replaced. This time the clock was stopped for six weeks. During the maintenance works the clock was driven by an electric motor.
2013 On 17 April, the bells were silenced during the funeral of Margaret Thatcher.
2015 The clock was discovered to be running seven seconds fast and some of the old penny coins that are balanced on the pendulum to regulate its swing were removed to correct the error. This caused the clock to to run slow for a time.
2017 Big Ben will be silenced and the clock will be stopped for several months while restoration works are carried out to repair the clock faces and the mechanism. Cracks in the masonry of the tower itself and the roof will also be repaired.