the official place of residence for the prime minister of India. The residence during the tenure of Nehru, the first prime minister, was Teen Murti Bhavan. Lal Bahadur Shastri chose 10, Janpath as an official residence. Indira Gandhi resided at 1, Safdarjung Road. Rajiv Gandhi became the first prime minister to use 7, Lok Kalyan Marg as his residence, which was used by his successors. Travel For ground travel, the prime minister uses a highly modified, armoured version of a Range Rover. The prime minister's motorcade comprises a fleet of vehicles, the core of which consists of at least three armoured BMW 7 Series sedans, two armoured Range Rovers, at least 8-10 BMW X5s, six Toyota Fortuners/Land Cruisers, and at least two Mercedes-Benz Sprinter ambulances. For air travel, Boeing 777-300ERs designated by the call sign Air India One (AI-1 or AIC001) and maintained by the Indian Air Force are used. There are several helicopters, such as Mi-8, used for carrying the prime minister over short distances. These aircraft are operated by the Indian Air Force. Protection The Special Protection Group (SPG) is charged with protecting the sitting prime minister and his/her family. The security is aided by the Central Reserve Police Force (CRPF), Border Security Force (BSF) and the Delhi Police to provide three-rung security for the estate. Office The Prime Minister's Office (PMO) acts as the principal workplace of the prime minister. The office is located at South Block, and is a 20-room complex, and has the Cabinet Secretariat, the Ministry of Defence and the Ministry of External Affairs adjacent to it. The office is headed by the Principal Secretary to the Prime Minister of India, generally a former civil servant, mostly from the Indian Administrative Service (IAS) and rarely from the Indian Foreign Service (IFS). Family The prime minister's spouse sometimes accompanies him/her on foreign visits. The prime minister's family is also assigned protection by the Special Protection Group, though it was removed after Special Protection Group Act in 2019. The most prominent of the family of prime ministers is the Nehru–Gandhi family, which has had three prime ministers, J. L. Nehru, Indira Gandhi and Rajiv Gandhi. Many family members of former prime ministers are politicians. Post-premiership Former prime ministers are entitled to a bungalow, and are also entitled the same facilities as those given to a serving cabinet minister, including a fourteen-member secretarial staff, for a period