Chennai, Sep 21 - S. Nalini, undergoing life imprisonment in the Vellore jail for her involvement in the assassination of former Indian prime minister Rajiv Gandhi, Monday started a fast to demand her immediate release from jail.

Nalini was awarded death penalty in 1991 but later at the intervention of Congress chief and Rajiv Gandhi's widow, Sonia Gandhi, the death sentence was commuted to life imprisonment.

Last week, Nalini, 43, had filed a petition in the Madras High Court asking for the Tamil Nadu government to convene the advisory board to consider her case for release from the jail.

In her petition, Nalini had said that she was entitled for release in 2005 itself as she had completed 14 years in jail.

In 2007, the state government had rejected her application for release and she had then filed a case in the Madras High Court in 2008.

The court directed the state government to reconsider her request for release by a validly constituted advisory board.