The uncoveries come amid a phased overhaul that began in April 2017 to replace boilers, electrical panels, cabling, water tanks and pipework, some unchanged since the 1950s. A 2016 estimate put the programme cost at about $487 million over 10 years. The palace stayed operational and was occupied part-time by Queen Elizabeth until her death in 2022. While some state visits moved to Windsor during works, the King will continue to hold audiences at Buckingham Palace, which will remain the ceremonial centre of royal life and aim to increase public access.