Although it looks like business as usual at Claridge's - one of London's most luxurious five-star hotels, set in the heart of Mayfair - beneath the surface of this iconic, elegant, exclusive hotel, filled with glamorous guests, who enjoy the finer things in life, is a busy building site. An extraordinary engineering project is underway, which seeks to add a five-story basement at the bottom and 72 new rooms and suites spread over three new floors at the top.But the owners are insistent that the hotel must remain open throughout the build, with the guests oblivious to the noise surrounding them - leading the miners to tunnel by hand. Filmed over six years, this series follows the building team and the hotel staff as they try to complete the build with as little disruption as possible to the hotel's array of high-profile guests.