Narendra Modi has not only become the longest-serving non-Congress prime minister of the country but he also has the longest tenure as head of an elected government, which includes his term of more than 12 years as Gujarat chief minister, among all PMs.

BJP sources pointed out on Friday that Modi's term first as chief minister and now as prime minister is over 18 years and 306 days as of now. Jawaharlal Nehru, the country's first prime minister who never headed a state government, served at the helm at the Centre for 16 years and 286 days.

Indira Gandhi comes third in the length of her tenure as an elected head of a government with a term of 15 years and 350 days as PM. Like her father, she was also never a chief minister.

Though there have been several chief ministers, including Jyoti Basu of West Bengal and Pawan Kumar Chamling of Sikkim, who have served for a longer period as head of an elected government than Modi but they were never prime minister.

With the BJP's preeminent leader set to serve as prime minister for at least four more years, his record is likely to stay for a very long time, sources said.