Former Foreign Secretary Sujatha Singh (R) and S Jaishankar, who has replaced her.
Subrahmanyam Jaishankar took over today as the new Foreign Secretary. Analysts say his appointment underscores the prime minister's intent for control over foreign affairs, a department that has seen much activity since he took power in May last year.
The abrupt sacking of Sujatha Singh has left her "upset and livid", say sources close to the 60-year-old.
Here is her farewell note to her colleagues: