Big Ben's famous bongs will be silenced for four years from next week so that major conservation work can be carried out.
The deafening chimes are being stopped to protect workers while they renovate the Elizabeth Tower that houses the Great Clock and its bell.
The clock will also be dismantled piece by piece and its four dials will be cleaned and repaired.
Abseiling technicians cleaning the faces of the Great Clock in 2014. Credit: PA
Big Ben's bongs will fall silent after sounding noon on Monday August 2.
Although they will still ring out for important national events such as New Year's Eve and Remembrance Sunday.
It will be the longest period the Great Bell has been silenced in its 157-year history.
The 13.7-tonne bell was last stopped for maintenance in 2007 and prior to that it was halted for two years in 1983 for refurbishment.
It has also been stopped accidentally on several occasions - by weather, workmen, breakages or birds - since it first sounded in 1859.
Steve Jaggs, keeper of the Great Clock, said: "Big Ben falling silent is a significant milestone in this crucial conservation project.
"This essential programme of works will safeguard the clock on a long term basis, as well as protecting and preserving its home - the Elizabeth Tower."
Members of the public have been invited to gather in Parliament Square to hear Big Ben's final bongs until they return in 2021.
As well as conservation work to Elizabeth Tower, the Great Clock will be dismantled piece by piece and its four dials will be cleaned and repaired.