Senior advocate Rohinton Nariman has resigned as Solicitor General of India amid speculation that the decision came over his differences with Law Minister Ashwani Kumar.

56-year-old Nariman, who was appointed as the Solicitor General (SG), the second seniormost law officer of the country, on July 23, 2011, sent his resignation letter to Prime Minister Manmohan Singh with a copy to the Law Minister.

Sources said that Nariman has not given any reason for quitting his post in his resignation letter.

There has been speculation that Nariman was unhappy over certain directions of the Law Minister Ashwani Kumar and the ministry. He is also believed to be annoyed over the way some of the government directions were reaching him.

When contacted, Kumar said, "I wish the very best to my colleague." The minister refused to say anything more on the resignation issue.

Official sources said resignation from an office is the sole discretion of an individual.

Nariman was appointed after the then SG Gopal Subramaniam had resigned on July 14, 2011.

Subramaniam had resigned as SG in the wake of Nariman being appointed as special counsel to represent Telecom Minister Kapil Sibal in a 2G related case in the Supreme Court, apparently without his knowledge.

Nariman is the son of eminent jurist Fali S Nariman.

He argued for Mukesh Ambani's RIL along with senior advocate Harish Salve in the dispute over the supply and pricing of gas from KG basin between the Ambani brothers.

Nariman was designated as a senior advocate at the age of 37 years in 1993 when the then Chief Justice of India M N Venkatachaliah amended the rules, for designating a lawyer as a senior advocate, by reducing the minimum age limit of 45 years.

He joined the Bar as an advocate in 1974 after completing his LL.B from Campus Law Centre, Delhi University, where he was among the toppers.

He had also gone to Harvard University for further studies.