After the war of words, the legal showdown has begun for one of India's biggest business battles.

The Supreme Court has begun hearing the gas dispute between Mukesh and Anil Ambani. In a packed courtroom, Harish Salve, who is representing Mukesh's Reliance Industries said: "Let the two promoters slug it out on their own. If Anil wants, he can sue Mukesh Ambani. Shareholders are not party to the dispute."

The dispute between the brothers is over whether Mukesh is obliged to sell gas at below-market rates to Anil. This is what was agreed upon when the brothers split their father's empire in 2005. Mukesh's legal team says the family agreement was not approved by Reliance's board.

Anil has led a high-pitched campaign over the past few months - first with a stormy speech at a shareholders' meeting and then with a slew of advertisements splashed on the front pages of newspapers which accused the government of siding with Mukesh.

Just ten days ago, Anil made a surprise truce offer to Mukesh in which he said he has "love and respect" for his brother. Mukesh rejected the offer, retorting that this is not a personal dispute.