Ageing cables, lead pipes, wiring and boilers are set to be replaced in the renovation, many for the first time in 60 years, after concern about potential fire and water damage.
The King and Queen have lived together in Clarence House, which stands beside St James’s Palace and was once the Queen Mother’s home, since their marriage in 2005.
Now both in their late 70s, it is understood that neither wanted the upheaval of moving themselves and their staff across to Buckingham Palace.
There are also security concerns that if the King was in residence at Buckingham Palace it would limit the number of visitors as well as areas people could view.
The landmark may now also be able to open for a longer period, generating more income. It currently opens its State Rooms to visitors each summer and selected dates throughout the rest of the year.
The King will continue to host a range of events at the palace from state banquets and garden parties to receptions and audiences with the prime minister and new ambassadors.
“His Majesty retains huge affection for Buckingham Palace and a deep respect for its role in royal and public life,” said the palace spokesperson. “It will be a buzzing hive of royal activity in every other way”.