Changing the clocks at Windsor Castle

A Horological Conservator adjusts an early-19th century French mantel clock in the Crimson Drawing Room at Windsor Castle. Royal Collection Trust / © His Majesty King Charles III 2023.

This weekend, Royal Collection Trust staff will spend over 30 hours changing clocks across the official residences of His Majesty The King as British Summer Time comes to an end. A busy team of three Horological Conservators will work through the weekend to adjust the clocks at Windsor Castle, Buckingham Palace, St James’s Palace and the Palace of Holyroodhouse.

The Royal Collection contains some of the finest historic clocks in existence, many of which are on display to visitors at Buckingham Palace, Windsor Castle and the Palace of Holyroodhouse. They include musical clocks, astronomical clocks, miniature clocks and turret clocks, and each must be carefully changed by hand to ensure that the times shown remain accurate for visitors, staff and residents.

Tjeerd Bakker, Senior Horological Conservator, said, ‘Clockmakers have been employed by the Royal Household for centuries, and it is a privilege to continue that tradition and to get to work with this extraordinary collection every day. Visitors love the fact that the clocks are kept running and on time; they are a key part of the experience of visiting the State Apartments at these working royal residences.’

A Horological Conservator adjusts the gallery clock in St George’s Hall at Windsor Castle. Royal Collection Trust / © His Majesty King Charles III 2023.

Clocks in the Royal Collection – facts and figures
• There are over 1600 timepieces in the Royal Collection, including 450 at Windsor Castle, 350 at the London residences of His Majesty The King and 50 at the Palace of Holyroodhouse that will need to be changed this weekend.
• In wintertime, it takes Windsor Castle’s Horological Conservator over 18 hours to change the clocks there, while at Buckingham Palace and St James’s Palace it takes a team of two a combined 16 hours.
• It takes longer to change the clocks in wintertime as not all clocks can have their hands rotated counterclockwise; the best practice for these clocks is to stop them and return an hour later to start them again.
• The clocks in the kitchens at Windsor Castle and Buckingham Palace are always set five minutes fast, to ensure that food arrives on time.
• The oldest clock in the Royal Collection is the Anne Boleyn Clock, which is reputed to have been given by Henry VIII to Anne Boleyn on the morning of their marriage in 1532.
• The smallest clocks in the Collection are the tiny clocks in Queen Mary’s Dolls’ House, which is on display to visitors at Windsor Castle. Made by Cartier, they measure just centimetres high and have working mechanical movements, but as they would need to be wound daily, they are kept static to prevent unnecessary wear and tear.
• The largest clock in the Collection is the Quadrangle clock at Windsor Castle, which was built by Benjamin Lewis Vulliamy in 1829 and installed during George IV’s extensive restoration of the Castle. The clock face has a diameter of 2.14m.
One of the most important timepieces in the Collection is known as Queen Charlotte’s watch. This unique pocket watch was the first to have a lever escapement and as such is the forerunner of almost all modern wrist and pocket watches.
• One of the most complex clocks is an 18th-century astronomical clock purchased by George III. The clock has dials on all four sides and is able to show time, strike the phase of the moon, the day and the date, and can show high and low tide in 32 ports around the world.

The Quadrangle clock at Windsor Castle is the largest clock in the Royal Collection. Royal Collection Trust / © His Majesty King Charles III 2023.