Editing Palace of Westminster (section)

==== Big Ben (Elizabeth Tower) ====
{{Main articles|Big Ben}}
[[File:Elizabeth Tower, June 2022.jpg|thumb|upright=0.75|The Elizabeth Tower (Big Ben)]]
At the north end of the palace is the Elizabeth Tower, commonly known by the nickname "Big Ben". At {{convert|96|m|ft}} it is only slightly shorter than the Victoria Tower, but much slimmer.<ref name="Factsheet G11" /> It was called the Clock Tower until 2012, when it was renamed to celebrate the [[Diamond Jubilee of Elizabeth II]]. The Clock Tower was designed by [[Augustus Pugin]] and built after his death. Charles Barry asked Pugin to design the clock tower because Pugin had previously helped Barry design the palace.<ref name="Taylor_BBC_Four">{{Cite episode |series=Pugin |title=God's Own Architect |url=https://www.bbc.co.uk/programmes/b01b1z45 |access-date=7 May 2021 |first=Richard |last=Taylor |author-link=Richard Taylor (British writer) |network=BBC Four |date=19 January 2012 |minutes=54 |language=English}}</ref>

The tower houses the Great Clock, which uses the original mechanism built by [[Edward John Dent]] to designs by amateur [[horologist]] [[Edmund Beckett, 1st Baron Grimthorpe|Edmund Beckett Denison]].<ref>{{cite web|url=http://www.parliament.uk/about/living-heritage/building/palace/big-ben/building-clock-tower/building-great-clock|title=Building the Great Clock|publisher=UK Parliament|access-date=14 May 2010}}</ref> It is highly accurate by nineteenth-century standards, striking the hour to within a second of the time, and remaining reliable since it entered service in 1859.<ref>[[#Macdonald|Macdonald (2004)]], pp. xiii–xiv.</ref> The time is shown on four dials {{Convert|7|m|ft|0}} in diameter, which are made of [[milk glass]] and are lit from behind at night; the hour hand is {{Convert|2.7|m}} long and the minute hand {{Convert|4.3|m}}.<ref>{{cite web|url=http://www.parliament.uk/about/living-heritage/building/palace/big-ben/facts-figures/great-clock-facts|title=Great Clock facts|publisher=UK Parliament|access-date=14 May 2010}}</ref> 

Five bells hang in the [[Belfry (architecture)|belfry]] above the clock. The four quarter bells strike the [[Westminster Chimes]] every quarter-hour.<ref>[[#Fell|Fell and Mackenzie (1994)]], pp. 24, 26.</ref> The largest bell strikes the hours; officially called the "Great Bell", it is generally referred to as Big Ben, a nickname of uncertain origins which, over time, has been applied to the whole tower. The original hour bell cracked during testing and was recast;<ref>{{cite web|url=http://www.parliament.uk/about/living-heritage/building/palace/big-ben/building-clock-tower/great-bell|title=The Great Bell – Big Ben|publisher=UK Parliament|access-date=14 May 2010}}</ref> the present bell later developed a crack of its own, which gives it a distinctive sound.<ref>[[#Macdonald|Macdonald (2004)]], pp. xvi–xvii, 50.</ref> It is the third-heaviest bell in Britain, weighing 13.8 tonnes.<ref>{{cite web|url=http://www.parliament.uk/about/living-heritage/building/palace/big-ben/facts-figures/great-bell|title=The Great Bell and the quarter bells|publisher=UK Parliament|access-date=14 May 2010}}</ref><ref>[[#Macdonald|Macdonald (2004)]], p. 174.</ref> In the lantern at the top of Elizabeth Tower is the Ayrton Light, which is lit when either House of Parliament is sitting after dark. It was installed in 1885 at the request of Queen Victoria, so that she could see from [[Buckingham Palace]] whether the members were "at work", and named after [[Acton Smee Ayrton]], who was [[First Commissioner of Works]] in the 1870s.<ref>[[#Jones|Jones (1983)]], pp. 112–113.</ref><ref>{{cite web|url=http://www.parliament.uk/visiting/online-tours/virtualtours/bigben-tour|title=Elizabeth Tower virtual tour|publisher=UK Parliament|access-date=15 May 2010}}</ref>