Funding for the Royal Family is to significantly increase over the next decade to pay for a £369m refurbishment of Buckingham Palace.
The Queen will remain in residence throughout the 10 years of works, which are due to begin in April 2017.
The Royal Household said the major refit was needed to "future-proof" the royal residence for the next 50 years, adding that an independent survey had warned there was a risk of "serious damage" to the palace unless urgent work was carried out.
The works include replacing some of the palace's 100 miles of electrical cabling, 30 miles of water pipes, 6,500 electrical sockets, 5,000 light fittings, and 2,500 radiators – many for the first time in 60 years.
The refurbishment was given the go-ahead by the Prime Minister, Theresa May, and Chancellor Philip Hammond. It is expected to be rubber stamped by Parliament in the next six months.
It will be funded by a temporary increase in the Sovereign Grant, from 15% to 25%. The grant is an allowance provided by the taxpayer to fund the Queen in her official duties.
Despite coming at a time of public sector pay freezes and government austerity, Tony Johnstone-Burt, Master of The Queen's Household, said the spend was "value for money".
He said: "The programme addresses parts of the structure you can't see from the outside: the plumbing, electrics and other essential building services which have gone six decades without a comprehensive upgrade.
"We take the responsibility that comes with receiving these public funds extremely seriously indeed; equally, we are convinced that by making this investment in Buckingham Palace now we can avert a much more costly and potentially catastrophic building failure in the years to come.
"We are also confident that our chosen option – the 10 Year Phased Refit – offers the best value for money whilst allowing the Palace to remain fully operational and occupied."
More than 15m tourists visit to Buckingham Palace each year and almost 100,000 attend as guests.
Major events including The Queen's annual garden parties, Trooping the Colour, State Visits, and Changing of the Guard will all continue as normal, the Royal Household said.