The Foreign Office is the government building on Whitehall, Westminster, finished in 1868, the same year Syndicate is set. It appears as a database landmark.
Scott came second in the 1857 design contest but got the job because Lord Derby liked his Gothic plans. When Palmerston became Prime Minister he demanded a Classical design, which Scott disliked, and the building went up in an Italianate style.
Walk Whitehall in Westminster: the Foreign Office sits among Horse Guards, Dover House, the Admiralty and Downing Street. It is not tied to a memory; reaching it unlocks the entry.
10 Downing Street
10 Downing Street is the Prime Minister's home and office in Westminster. In 1868 Benjamin Disraeli lives here, and Jacob's work as his bodyguard in Sequence 7 starts outside the house.
Admiralty
The Admiralty is a government office on Whitehall in Westminster, one of the period buildings you can climb and read about in the in-game database. No memory centres on it.
Banqueting Hall
The Banqueting Hall, later the Chapel Royal, is a 1622 hall on Whitehall in Westminster and a database landmark in Syndicate. It is the only surviving part of the old Palace of Whitehall.
Blue Anchor Alley
Blue Anchor Alley is a Blighter stronghold in Westminster run under Lilla Graves, one of two in that borough. Freeing it lets the Rooks set up there instead.