Located on the western side of Government House adjacent to Rajdamnern Road, this group is built on the former site of the Chulachomklao Military Academy, which was later moved to the province of Nakhon Nayok during the premiership of Gen. Prem Tinsulanonda that approved the extension of Government House on this property. Today, it houses agencies under the Secretariat of the Prime Minister, Secretariat of the Cabinet, and the National Security Council.
The initial group comprises three red-painted European-style buildings adjacent to each other built during the reign of King Chulalongkorn (King Rama V). The central building, called Red Building 1, is a three-story structure with its gables decorated with the personal emblem of King Chulalongkorn, a coronet, or Phra Kiao, and below this the emblem of the first Infantry Regiment. Currently, it serves as the Office of the Secretariat of the Prime Minister. To its right is Red Building 2, which is now used as the Office of the Secretariat of the Cabinet, including the Royal Thai Decorations Museum. On the left side of the central building is Red Building 3, the headquarters of various agencies under the Secretariat of the Prime Minister.
Later, during the premiership of Mr. Banharn Silpa-Archa, two more buildings were built under the supervision of the Fine Arts Department to blend with the original three. Red Building 4 was constructed behind Red Building 3 and houses the Office of the Secretariate of the Cabinet while Red Building 5, built behind Red Building 1, serves as the headquarters of the National Security Council.
After Field Marshal Sarit Thanarat became Prime Minister, the government built guesthouses in several provinces, one being Baan Laem Thaen in the province of Chonburi. This later became a retreat for the field marshal before his death in 1963. Before this, it was often used to host cabinet meets as well as as a “War Room” when the government needed a situation room to monitor certain world events. Later, when Field Marshal Thanom Kittikachon became Prime Minister, all the different guesthouses fell under the supervision
of the Prime Minister’s Secretariat.
Baan Laem Thaen has played an important role in international affairs as the government of Field Marshal Thanom worked to help establish the Association of Southeast Asian Nations (ASEAN). At that time, Dr. Thanat Khoman served as the country’s foreign minister and hosted a meeting here with his counterparts from Malaysia, the Philippines, Indonesia and Singapore on 6 August 1967, after which they issued a joint declaration known as the “Spirit of Bang Saen”, which led to the establishment of ASEAN.