You can take a tube, train, or bus to reach the Churchill War Rooms.
By tube/train: The nearest tube station is Westminster which is only 5 minutes away by walk, while the closest train station is Charing Cross which is 12 minutes away by walk.
By bus: You can take bus routes 3, 11, 12, 24, 53, 87, 88, 109, 148, 159, 184, 211, and 453 to reach the Churchill War Rooms. The nearest bus stop is Westminster Station, which is only a 5-minute walk away.