Brothers in court: Billionaire blood feud

They were born just two years apart, grew up together in humble circumstances and rose to become the wealthiest brothers in the world. So why can't the Indian industrialists Mukesh and Anil Ambani – ranked the fifth and sixth richest people on the planet – get along?

In the latest twist to the pair's notoriously acrimonious relationship, Anil has reportedly filed a £1bn defamation lawsuit against his elder brother. The legal action relates to an interview that Mukesh gave to a US newspaper earlier this year in which it is alleged he made disparaging and defamatory comments about his brother. "A suit has been filed but it has yet to be admitted by the High Court [in Mumbai]," an industry source with direct knowledge of the action said last night.

The Ambanis are the sons of the late industrialist Dhirubhai Ambani. When their father died six years ago, he left the business empire he had built up over decades jointly to his two sons. But the increasingly bitter relationship between the pair forced them to divide the family silver three years after their father's death and go their separate ways.

Mukesh, 51, heads Reliance Industries (RIL) – India's biggest private company which focuses on supermarkets, manufacturing and the petroleum businesses – while 49-year-old Anil is the boss of the Reliance Anil Dhirubhai Ambani Group (Reliance AGA), specialising in telecommunications and banking.

Each brother runs his half of the former empire independently of the other. Yet even with things divided, the acrimony has continued with allegations and counter-accusations regularly hurled across the business pages of India's newspapers. The accusations usually focus on alleged mismanagement but the bad blood has even allegedly forced Mukesh and his wife, Nita, to leave the long-time family mansion Sea Winds, in Mumbai, and set up home on their own.

In typical Ambani fashion, Mukesh – who also owns the Mumbai Indians cricket team – is building a 27-storey house that will be the world's most expensive private property. The £500m home will have its own helipad, parking for hundreds of cars and an entire floor for his mother. It will not have a room for his brother.

The alleged defamation that has prompted the lawsuit is said to have taken place in a rare interview that Mukesh granted to The New York Times. Reports say that after the article appeared, Anil Ambani's lawyers wrote to the newspaper demanding a "clear, unambiguous and unqualified" retraction and an apology from Mukesh. In the legal papers, a total of 10 people are apparently named, including the newspaper's editor, publisher and the reporter who carried out the interview in Mumbai.

Anil Ambani's company has yet to comment publicly on the action and a spokesman for Mukesh's RIL told reporters that it had not received details of any such lawsuit. A spokeswoman for The New York Times said: "Since we have not yet received a copy of the suit, we cannot comment on it."

While Mukesh Ambani prefers to keep a low profile he is known for his high-spending ways. In addition to his multistorey house, he hit the headlines last year when it was reported that he bought a £30m private jet for his wife's birthday. Anil Ambani, who is married to a former Bollywood model, appears more at ease in the public eye. He is often spotted in the early morning, jogging along the seafront in Mumbai, his chauffeur-driven car following behind. While rumours often swirl about a reconciliation between the brothers, the latest events mean that could be some way off.

The elder: Mukesh

At 51, Mukesh is reportedly worth $43 bn. At one point the head of Reliance Industries, India's largest private company, overtook Bill Gates to become the world's richest man. These days he is the fifth.

The younger: Anil

Worth a reported $42bn, Anil, 49, is a step behind his older sibling. Running the other half of his late father's empire, there has been speculation in recent weeks that he is seeking to expand into the English Premier League. He has been linked in recent weeks with both Newcastle United and Everton.