Big Ben bongs to be silenced as engineering works reach critical stage

As part of the complex series of works, the tower’s Great Clock will be dismantled piece by piece with each cog examined and restored. The four dials will be carefully cleaned, the glass repaired, the cast iron framework renewed, and the hands will be removed and refurbished. A modern electric motor will drive the clock hands until the Great Clock is reinstated.

The Great Clock, considered by many to be one of the finest and most innovative mechanical clocks ever to be built, is operated by a custom-built Victorian mechanism that relies on gravity to trigger the renowned bongs.

READ THE ENGINEER’S ARCHIVE COVERAGE ON BIG BEN HERE

To stop the bells the striking hammers will be locked and the bell disconnected from the clock mechanism, allowing the Great Clock to continue telling the time silently. Parliament’s specialist clock makers will ensure that Big Ben can still bong 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.

The Great Bell, popularly called Big Ben, weighs 13.7 tonnes and strikes every hour to the note of E. It is accompanied by four quarter bells, which chime every 15 minutes.

Cast at the Whitechapel Bell Foundry in 1858, Big Ben weighs 13.7 tonnes and is one of the largest bells in the UK.

The current Big Ben is actually the second Bell manufactured for the tower. An earlier bell, cast in 1856, was irreparably damaged thanks to the original striking hammer being too heavy.

The bongs last fell silent for maintenance in 2007, and prior to that between 1983-5 as part of a previous large-scale refurbishment programme.

Commenting on the current works, Steve Jaggs, Keeper of the Great Clock, said: "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."