A Victorian Masterpiece
The Great Clock was designed by Edmund Beckett Denison (later Lord Grimthorpe) and built by Edward and Frederick Dent. Installed in 1859, it was then the very height of horological innovation. Its ingenious double three-legged gravity escapement allowed the movement to drive four immense dials — each 22 ½ feet in diameter — while keeping time to within a second of the hour.
The great bell itself, cast by Whitechapel Bell Foundry, soon developed a crack after being struck with too heavy a hammer. Rather than replace it, the bell was turned and fitted with a lighter hammer, giving it the distinctive tone that millions now recognise instantly as “Big Ben.” Meanwhile, the Westminster quarter chimes — adapted from Great St Mary’s in Cambridge, where Denison had studied — went on to become one of the world’s most familiar melodies.
The Hard Work of Winding
Behind the precision lay immense physical effort. For more than 50 years, the Great Clock was wound entirely by hand, a gruelling task that required two men turning handles thousands of times each week to lift the three giant weights that powered the going, striking, and quarter trains. Their labour left permanent footprints worn into the wooden floor of the clock room.
In 1913, Dent & Co. installed one of the earliest electro-mechanical winding systems, a pioneering piece of engineering that reduced four hours of winding to just 40 minutes. Over a century later, this system remains an essential part of the clock and was itself overhauled as part of the recent restoration.
The Largest Restoration in History
From 2017 to 2022, the Elizabeth Tower underwent its most comprehensive programme of conservation since completion. The project began with the recognition that the Great Clock itself required urgent attention. Once scaffolding was erected around the 320-foot tower, it became possible to expand the works to include masonry, cast ironwork, gilding, stained glass, and decoration.
At the heart of the horological work was the Cumbria Clock Company working alongside the Palace Clock Team, entrusted with dismantling, conserving, and reinstating the five-ton clock mechanism.
The team carefully removed the 15-foot pendulum, the three massive barrels, the dial motion works, and the great hands. Piece by piece, the mechanism was lowered 175 feet down the weight shaft and transported, in secrecy, to Cumbria. Security was tight: such was the fame of the clock that even a single stolen component could have become a trophy.
Conservation in Cumbria
In the Lake District workshops, the Cumbria and Palace team undertook painstaking conservation. Every part was cleaned using specialist methods such as aqua blasting and dry ice cleaning, revealing original finishes and exposing areas that required repair. Worn teeth, pivots, and bushes were repaired or remade with traditional techniques. Bespoke cradles and rigs were designed to move the immense components safely, while full-scale outdoor testing rigs were built to trial the 22-foot dial motion works.
The 1913 electro-mechanical winding system, that had not been operating automatically for several decades, was also disassembled, studied, and restored to full working order. Its ingenious epicyclic gearing, clutch mechanisms, and cams were documented in detail so future clockmakers would understand its complexity.
Throughout, Cumbria Clock Company compiled a photographic archive of over 3,000 images and produced full engineering drawings, ensuring this knowledge will never be lost.
Keeping Time While Standing Still
While the clock was dismantled, the tower itself could not fall silent. To preserve its iconic presence, Cumbria Clock Company manufactured temporary drive units and replica hands, ensuring that at least one dial always showed the correct time. These replicas were so faithful that visitors could not tell the difference.
Equally important was a temporary tolling unit, designed to allow the great bell to sound on key national occasions. Thanks to this, Big Ben continued to strike on Remembrance Sunday and New Year’s Eve, even with the historic movement in Cumbria. The tolling system carefully replicated the hammer lift, protecting the cracked bell while ensuring its voice still rang out across the capital.
The Clock Returns
In 2021, the long process of reinstallation began. The restored motion works and newly painted hands were lifted back into place on Pugin’s dials, now repainted in their original Prussian blue and gold. The pendulum was rehung, the barrels replaced, and by Christmas the going train was ticking once more — the heartbeat of the UK restored to its rightful home.
Today, the clock keeps time with astonishing precision, regulated to within hundredths of a second. Its strike resounds louder and clearer than in living memory, thanks to the restoration of its hammer assemblies. When Big Ben tolled for the funeral of Queen Elizabeth II in September 2022, synchronised precisely with ceremonial field guns, it was the Cumbria team’s craftsmanship — both temporary and permanent — that ensured the nation’s most famous bell marked the moment with dignity.
A Living Symbol
The Great Clock of Westminster is far more than a timekeeper. It is a national symbol, a monument to Victorian ingenuity, and a beacon of traditional skills — stonemasonry, glassmaking, gilding, and above all horology.
Thanks to the dedication of the Cumbria Clock Company, the Palace Clock Team and the many craftspeople who contributed to its conservation, Big Ben will continue to strike across London and around the world for generations to come.
