St. Ermin's Hotel is a four-star central London hotel adjacent to St James's Park Underground station, close to Westminster Abbey, Buckingham Palace, and the Houses of Parliament. The Grade II-listed late Victorian building, built as one of the early mansion blocks in the English capital, is thought to be named after an ancient monastery reputed to have occupied the site pre-10th century. Converted to a hotel in 1896–1899, it became during the 1930s, through the Second World War and beyond, a meeting place of the British intelligence services, notably the birthplace of the Special Operations Executive (SOE), and where notorious Cambridge Five double agents Philby and MacLean met their Russian handlers. St Ermin's is now part of Marriott Hotels' Autograph Collection. The hotel is owned by the family of Tei-Fu Chen, founder of Sunrider International.

Special Operations Executive (SOE) was a British organisation formed in 1940 to conduct espionage, sabotage and reconnaissance in German-occupied Europe and to aid local resistance movements during World War II.