Big Ben's Great Clock celebrates its 160th Birthday

Parliament's team of expert clock mechanics has taken the Great Clock apart piece by piece to undertake a complete overhaul of all the components, as restoration continues on the Elizabeth Tower.

Thousands of components weighing over 11 tonnes were winched down from the Tower before work could begin, ensuring the clock mechanism was protected from grit and dust during the wider works to conserve the Elizabeth Tower. An electric motor has been temporarily installed to drive the hands of the clock whilst the mechanism is restored.

When the essential work to conserve the Elizabeth Tower is completed, the clock parts will start making the journey back up the Tower to be reassembled, and the mechanism will be reattached to the hands and the bells.

Ian Westworth, Clock Maker in Parliament, said: “After 160 years of near continuous use the clock mechanism is in remarkably good condition. It has been well looked after over the years, but now we are cleaning, inspecting, painting and testing every single cog and wheel to ensure it can continue keeping time for the nation for another 160 years and beyond.”

History of the clock

In 1846 a competition to design and build the clock mechanism was held, overseen by the Astronomer Royal, Sir George Airy. Airy wanted to see the most accurate turret clock in the world, and stipulated that it must be accurate to within one second.

Clockmaker Edward John Dent was subsequently appointed to build the clock to the design of Edmund Beckett Denison, a barrister and amateur clockmaker. Dent died soon after, and his stepson, Frederick, completed the clock in 1854.

The clock was installed in the Tower in 1859, after Denison had made many refinements, including inventing the 'Double Three-legged Gravity Escapement'. This was a revolutionary mechanism, ensuring the clock's accuracy by making sure its pendulum was unaffected by external factors, such as wind pressure on the clock's hands.

Essential conservation works

Standing at 96 metres tall, the Elizabeth Tower is a focal point of the Grade I listed Palace of Westminster, which forms a part of a UNESCO World Heritage site. Not only is it a world famous landmark, it is also one of the most photographed buildings in the UK.

Essential conservation work is now underway to:

• Repair problems identified with the Elizabeth Tower and the Great Clock, which cannot be rectified whilst the clock is in action.
• Conserve significant elements of the Tower, as designed by architects Charles Barry and Augustus Welby Pugin.
• Repair and redecorate the interior, renew the building services and make improvements to health and safety and fire protection systems.
• Improve energy efficiency to reduce the Tower's environmental impact.

Further information

For further information on the Elizabeth Tower, the Great Clock and Big Ben visit our website here.