Led by its U.S.-educated chairman, Tata Group is modernizing operations and making overseas acquisitions as it plugs into the world economy.

LONDON — No one has done more to announce India's arrival on the international business stage than Ratan Tata, chairman of Tata Group, the country's largest conglomerate.

Last month the group unveiled one of the biggest overseas acquisitions in Indian corporate history: the $239-million purchase of Teleglobe, a Bermuda-based wholesale telecommunications company. The two biggest acquisitions by Indian companies abroad are also Tata deals: the $432-million purchase of Britain's Tetley Tea in 2001 and the $289-million acquisition of Singapore's NatSteel in 2004.

The Teleglobe deal is another milestone for a man who last month surprised the business world by announcing his intention to remain in office beyond his expected retirement date in 2 1/2 years. In a rare interview, Tata, 67, told the Financial Times why he was staying on and what he hoped to achieve before handing the reins to a successor.

An architect educated at Cornell University in New York, Tata is hurt by suggestions that he is clinging to power. He says non-executive directors warned him that unless the retirement age was raised from 70 to 75, the group would face a sudden loss of experienced executives.

"I really am unlikely to stay on for the full period," Tata said. He gives the impression that he has set himself a final set of goals.

Tata's ambition is to make Tata Group fit for global competition by transforming its operations at home and plugging it into the world economy. Even if he stays on for the full extra five years, he is unlikely to see that process completed. But he wants to advance it before leaving.

Tata Group is already barely recognizable from the antiquated behemoth of 1991, when Tata inherited the chairmanship from his uncle, J.R.D. Tata. He recalls the situation then with barely disguised horror. Tata Group was an empire in name only. Powerful executives ruled the operating companies, merely paying lip service to the group. The board was full of elderly dignitaries. "Some of them fell asleep during meetings," he said.

Tata wrested back management control, used cash flow from the booming software unit, Tata Consultancy Services, to rebuild group shareholdings and pushed the industrial companies to invest and modernize.

Then Tata stepped out into the world with the Tetley deal. No Indian company had ever attempted anything so ambitious. It was a big success.

"I do not think that at any stage I expected the integration to be as good and as robust as it has turned out to be," Tata said. "This has become a model for several of our other acquisitions."

Since then Tata Group has bought NatSteel, Daewoo Motors' truck operations, a motor coach manufacturer in Spain, the Tyco global cable network — and now Teleglobe.

The acquisition spree represents growing confidence in Tata Group's prospects. Three of its big companies — Tata Consultancy Services, Tata Motors and Tata Steel — are generating good profits. But VSNL, the fixed-line telecom unit, is not, and Tata Group still has many underperforming businesses.

The sheer complexity of the group — it has 91 operating companies — forces Tata to grapple with a bewildering array of challenges. At the top of the list is Tata Motors' bid to develop a people's car for the developing world. The project, widely seen as Tata's own, is regarded as an expensive gamble. But Tata remains bullish.

He says the company has been able to offset high steel prices by using more plastic and sourcing parts from China. He insists that the car will be launched in three years with a price of about 100,000 rupees (about $2,200).

Meanwhile, Tata and his executives have to work out what to do in Britain, where Tata Motors' attempt to sell higher-value cars in partnership with MG Rover Group came unstuck. Tata Motors is now talking to distributors about selling cars in Britain under its own brand.

There is a lot more in his in-box. Last year, Tata Consultancy went public in India with an initial stock offering that raised a record $1.2 billion.

Tata says it would be logical to follow this by listing in the United States. But he is frustrated by the market's focus on short-term earnings. He wants to be "absolutely sure we have all our strategy in place" before adding to the scrutiny by listing in the U.S.