People record the last bell bong at Elizabeth Tower in London, Monday, Aug. 21, 2017. At noon, Big Ben's famous bongs sounded for the last time before major conservation works are carried out. The Elizabeth Tower, home to the Great Clock and Big Ben, is currently undergoing a complex programme of renovation work that will safeguard it for future generations. While this vital work takes place, the Great Bell's world famous striking will be paused until 2021 to ensure the safety of those working in the Tower.(AP Photo/Frank Augstein)
People record the last bell bong at Elizabeth Tower in London, Monday, Aug. 21, 2017. At noon, Big Ben's famous bongs sounded for the last time before major conservation works are carried out. The Elizabeth Tower, home to the Great Clock and Big Ben, is currently undergoing a complex programme of renovation work that will safeguard it for future generations. While this vital work takes place, the Great Bell's world famous striking will be paused until 2021 to ensure the safety of those working in the Tower.(AP Photo/Frank Augstein) Credit: Frank Augstein

London — After more than 150 years as Britain’s most famous timekeeper, London’s Big Ben bell fell silent on Monday for four years of repair work that will keep it quiet on all but a few special occasions.

The giant bell atop Parliament’s clock tower sent a dozen deep bongs into a gray sky at noon, marking the hour as it has done almost continuously since 1859. It is not due to resume its regular duties until 2021.

Hundreds of parliamentary staff, journalists and lawmakers gathered in a courtyard under the Victorian clock tower to mark the moment, while hundreds more tourists and passers by lined sidewalks and filled nearby Parliament Square, cellphones held aloft.

The mood was light-hearted — it is, after all, just a bell — but total silence fell as the first bong sounded. The crowd burst into cheers and applause as the last faded away, and bells at nearby Westminster Abbey pealed a noisy farewell to their neighbor.

The bell is being stilled to allow workers to carry out much-needed maintenance to the clock and clock tower without being deafened. But a handful of lawmakers have criticized the lengthy silence, calling Big Ben an important symbol of British democracy.