LONDON -- Big Ben will fall silent next week in London as a major restoration project gets underway.

The bongs of the iconic bell will be stopped on Aug. 21 to protect workers during a four-year, $38 million conservation project that includes repair of the Queen Elizabeth Tower, which houses Big Ben and its clock.

Steve Jaggs, keeper of the Great Clock, said Monday that the mechanism will be dismantled piece by piece and its four dials will be cleaned and repaired.

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Big Ben has been stopped several times since it first sounded in 1859, but the current restoration project will mark the longest period of silence for the bell.

It will still sound on big occasions, such as Remembrance Sunday.

Jaggs said last year when the renovation plans were announced that it couldn't wait much longer.

"The tower is not unstable," he said. "But unless we do something now it's going to get a lot worse.

"We need to do the work pretty soon to keep this for future generations to enjoy."

Jaggs said the renovation would include work to repair corrosion to the cast-iron roof and stop water seepage that threatens to "blow chunks" of stonework from the iconic 160-year-old building.

The huge clock will be stopped for several months so that Parliament's clockmakers can work on the 13-foot pendulum and remove the hands from each of the four faces.

The 13.5 ton Big Ben bell will cease to sound the hours for the next four years however, while it is cleaned and checked for cracks.

Officially named the Elizabeth Tower in honor of Queen Elizabeth II, the structure is one of London's most famous landmarks. It became a symbol of defiance when it survived German bombing raids during World War II -- though one of the four clock faces was blown out.

The tower is popularly known as Big Ben, though that is actually the name of the largest of its five bells. The four smaller bells chime the quarter hours, while Big Ben bongs out the hour.

The sound of the bongs became associated with Britain around the world during wartime BBC news broadcasts, and is still played live each day on BBC radio through a microphone in the belfry.

In October 2015, when worries over the condition of the clock tower first seeped into the mainstream press, British newspaper columnist Quentin Letts told CBS News that stopping Ben Ben would be like stopping the heartbeat of London.

"This is the marrow in our bones, this old clock," said Letts. "The thought of it not being there, or one hand flying off, or heaven forbid, the thing going digital, is just too gruesome to consider."

Jaggs said workers would make sure that Big Ben still chimes at midnight on New Year's Eve throughout the renovations.

The repair work will use traditional methods and materials as much as possible, but a couple of modernizations are planned.

The 28 lightbulbs behind each clock face will be replaced with energy efficient LED bulbs that can change color, so the clock tower can be tinted to mark major celebrations or commemorations.

And there are plans to install an elevator in a ventilation shaft. Currently the only way to the belfry is up a 334-step circular staircase.

The tower repairs are only a small part of the work that needs to be done to shore up a Parliament complex beset by damp and decay.

A report released in 2015 said the 19th-century neo-Gothic structure needed major repairs that could cost up to 7 billion pounds ($11 billion) to remove the risk of a "catastrophic failure." One option under discussion would see lawmakers move out for up to six years while the work is done.

Jaggs said that even if the rest of the building is empty and under scaffolding, the tower "will still be a beacon of democracy around the world."