Big Ben’s famous bongs will temporarily cease for four years from next week so that major conservation work can be carried out.

To mark this important step in the critical conservation of the Elizabeth Tower, people are invited to Parliament Square at noon on August 21 for a last chance to hear the Great Bell strike midday until 2021.

While vital restoration work takes place, 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 Tower.

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 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 programme.

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.