The hour bell of the Great Clock of Westminster, known worldwide as Big Ben, is one of the most famous bells ever cast at the Whitechapel Bell Foundry. It measures 9 feet in diameter, 7 feet 6 inches high, and weighs nearly 13.8 tons (13,760 kg). This painting by William T. Kimber, head moulder of the bell, shows George Mears with his wife and daughter inspecting the casting before it was sent off. Big Ben was cast on April 10, 1858, but its story began more than a decade earlier.

In 1844, Parliament decided the new Houses of Parliament, then under construction, should include a tower and clock. Architect Charles Barry was commissioned to design the building, while the Astronomer Royal, George Airy, specified that the hour bell’s first stroke must keep time accurate to within one second per day and telegraph its performance twice daily to Greenwich Observatory. Most clockmakers doubted such accuracy was possible for a large tower clock. It wasn’t until 1851 that Edmund Beckett Denison (later Sir Edmund Beckett, Baron Grimthorpe) was found who could meet this challenge.

Denison’s clock, built by E.J. Dent & Co., was completed in 1854. However, the bells presented a challenge. Barry had specified a 14-ton hour bell but made no plans for its production or the four smaller quarter bells. Denison had his own ideas on bell design and metal composition, differing from traditional methods. John Warner & Sons initially cast a 16-ton bell in 1856, but it cracked during testing.

George Mears, master bellfounder and owner of Whitechapel Foundry, was then commissioned to recast the bell. The metal from the first bell was reused, lowering the casting cost. The mould was heated before casting—a first in British bell-founding. The molten metal filled the mould in 20 minutes, but the bell took 20 days to cool. After testing, Denison approved it.

Transporting the bell through London was a grand event. Drawn by sixteen horses and cheered by crowds, it passed over London Bridge and Westminster Bridge, with streets decorated for the occasion.

The bells first rang across London on May 31, 1859. During a special parliamentary session to name the hour bell, Sir Benjamin Hall—large and well-known as “Big Ben”—gave a lengthy speech. As he sat down, someone joked, “Why not call him Big Ben and have done with it?” The name stuck, though some believe the nickname could also refer to Benjamin Caunt, a famous heavyweight boxer of the era.

Just two months later, Big Ben cracked. Denison blamed his heavy hammer (more than twice the recommended weight). The bell was taken out of service, with the hours struck instead on the largest quarter bell for three years. Eventually, a lighter hammer was fitted, a small piece was chipped from the bell’s soundbow, and the bell was rotated slightly to present an undamaged section. This cracked bell is the one we hear today, giving Big Ben its distinctive tone.

Denison tried to blame poor casting, persuading a moulder to give false testimony, leading to a court case he lost. He continued to criticize the foundry and lost a second libel trial twenty years later.

In 2002, a transcript from the second trial, Stainbank v Beckett (1881), was found, shedding light on this dramatic history. The foundry still displays a small model used to demonstrate bell casting principles.

Big Ben remains the largest bell ever cast at Whitechapel. Visitors to the foundry can see a full-size profile of the bell framing the entrance and the original moulding gauge used for casting hangs above the furnaces to this day.