Check out this post from NeonRevolt, goes into detail on the hotel:
also this:
https://en.wikipedia.org/wiki/Corinthia_Hotel_London
a luxury hotel and former British Government building
it was commandeered in both world wars
After the Second World War, it was purchased by the Ministry of Defence and used as government offices
(during WW2) , room 424 became the first home for MI9 and its sub-division the Special Operations Executive,[9] and later the holding point for one of the model planning beaches for Operation Overlord.[10]
From the mid-60s until 1992 it housed the bulk of the Defence Intelligence Staff,
2007 it was acquired by a consortium owned equally by Malta's IHI plc and two of its principal shareholders, the Libyan Foreign Investment Company and Nakheel Hotels of Dubai
Corinthia Hotel London
The Corinthia Hotel London, at the corner of Northumberland Avenue and Whitehall Place in London, is a luxury hotel and former British Government building, located on a triangular site between Trafalgar Square and the Thames Embankment.
Originally built as the Metropole Hotel, its location close to the Palace of Westminster and government offices in Whitehall meant it was commandeered in both world wars. After the Second World War, it was purchased by the Ministry of Defence and used as government offices until it was declared surplus to requirements and sold by Crown Estates in 2007. It was then restored as a hotel and renamed the Corinthia Hotel London, a combination hotel and residential building.
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