Photo taken on April 27, 2016 shows the Big Ben in central London, Britain. [Photo/Xinhua]

LONDON - London's famous Big Ben will chime for the last time on Monday (Aug 21) when the famous Great Bell falls silent until 2021.

Officials at the Houses of Parliament issued an invitation to the public Monday to gather in Parliament Square in a week's time to hear the final bonging this decade of the iconic bell, one of the best known symbols of Britain's political focal point.

The silence of the bells has been ordered to enable vital restoration work to take place.

It means the Great Bell's world famous strikes and the chimes of the quarter bells will be paused for several years to ensure the safety of those working in the Elizabeth Tower which houses the bells and the clock.

Steve Jaggs, Keeper of the Great Clock said: "Big Ben falling silent is a significant milestone in this crucial conservation project. This essential program of works will safeguard it on a long term basis, as well as protecting and preserving the Elizabeth Tower."

"Big Ben has marked the hour with almost unbroken service for the past 157 years. The bell last fell silent for maintenance in 2007, and prior to that between 1983-5 as part of a previous large scale refurbishment program."

Explaining how the bells will be silenced, a spokesman at the Houses of Parliament said: "To stop the bells the striking hammers will be locked and the bells disconnected from the clock mechanism, allowing the Great Clock to continue telling the time silently.

"Parliament's expert clock mechanics will ensure that Big Ben can still bong, and the quarter bells chime, for important national events such as New Year's Eve and Remembrance Sunday. The bells will resume their regular time keeping duties in the course of 2021.

"Whilst the Great Clock and the dials are undergoing conservation, it will be necessary to cover the faces for some time. However, to ensure that the public are still able to set their watches by this most important of time pieces, one working clock face will remain visible at all times throughout the works. As the clock mechanism itself will be temporarily out of action, a modern electric motor will drive the clock hands."