Ms Jayalalithaa is likely to be sworn in as Tamil Nadu chief minister on Sunday, May 17, an auspicious date according to sources in her party, the AIADMK.

"I am immensely satisfied with the verdict... Verdict paved way for me to emerge like tested pure gold," said Ms Jayalalithaa. The 67-year-old was found not guilty in a nearly two-decades-old case of corruption by the Karnataka High Court today. She had been convicted last year by a Bangalore court.

The trial was held in Karnataka to ensure it was not influenced by the considerable clout her party, the AIADMK, has in Tamil Nadu.

According to some reports, the judge today declared her not guilty within 10 seconds. Three others who had been convicted along with her, including close aide Sasikala Natarajan, have also been acquitted.

In September, a Bangalore judge found Ms Jayalalithaa guilty, during her first term as Chief Minister in the 90s, of disproportionately massing assets worth Rs. 54 crore outside her known sources of income. He sentenced her to four years in jail, and fined her Rs. 100 crore. She was granted bail by the Supreme Court after spending three weeks in jail.

That verdict meant that she was disqualified as an elected representative and obliged to step down as Chief Minister. Today's acquittal paves the way for her return to office, but she will have to contest elections within six months.

Prime Minister Narendra Modi called Ms Jayalalithaa this afternoon to congratulate her on her acquittal. Foreign Affairs Minister Sushma Swaraj and NCP chief Sharad Pawar also spoke to her.

Fireworks and celebrations filled the air outside the former Chief Minister's home in Chennai, where top AIADMK leaders showed up within minutes of the verdict being announced. They included O Panneerselvam, the loyalist picked by Ms Jayalalithaa as her replacement, who has refused to use her office, and made it clear that he considers himself a seat-warmer.

The case against her had been filed by Subramanian Swamy, a leader of the BJP, who has indicated he will appeal against her acquittal in the Supreme Court.