Sir Terry Leahy has started 2006 with a bang.

First was the announcement that the chief executive - having repeatedly downplayed such ambition - was going to take Tesco to the US.

This week brings news that Sir Terry is also mulling a move in India, the world's eighth-biggest retail market and a clear emerging global power.

The fact that Tesco is considering linking up with Bharti Enterprises suggests the chain, having built an seemingly unassailable position in the UK, is becoming more aggressive about overseas expansion. Tesco refused to comment yesterday.

It has taken the UK's biggest supermarket chain 12 years build up its network across 13 countries in Asia and Europe.

Sir Terry has used a combination of organic growth in Hungary, Poland and Malaysia and joint ventures with Samsung in South Korea and Hymall in China. This has enabled him to build an international business turning over £7.6bn a year and contributing 20 per cent to underlying group profits.

Now Tesco seems to be stepping up a gear as it looks to enter two of the world's largest markets in the coming year.

It has also expressed interest in buying stores from Carrefour in South Korea thought to be on the auction block.

Some observers question whether the retailer is biting off more than it can chew. They fear it is reminiscent of Carrefour in the 1990s, which expanded at two countries a year for a decade, only to then begin a retrenchment process when it became clear that the French chain had over-extended.

As one retail expert puts it: "Twelve months ago the criticism of Carrefour compared with Tesco was that the former had too many activities in too many countries that were not being supported. Tesco was considered much more focused; but now you could start thinking it could become the opposite way round."

Sir Terry, having doggedly advocated his strategy of only entering emergingmarkets with fragmented local competition, a bigpopulation and the potential for plenty of economic growth to boost consumer spending, has changed his tune with his surprise US move.

The US retail market is the largest and one of the most competitive in the world with mature incumbents. It is not obvious Tesco turf.

Analysts say Japan, the other market where Tesco has adopted the convenience store approach, has been one of its least impressive overseas ventures.

If it comes off, the Indian deal will also be uncharted territory. Because foreign direct investment in the retail sector is banned - the government is close to allowing single-brand speciality retailers - Tesco will have to enter a franchise agreement with Bharti.

That could see Tescoselling its products through Bharti's stores but notowning a stake in theinfrastructure.

However, it would provide Tesco with a head start against competitors also trying to enter India.

Moreover, the Indian market, set to grow to $411bn (£235bn) within five years according to Technopak, a retail consultancy, is ripe for business.

It is also extremely fragmented, with organised retailing accounting for only 2 to 3 per cent of the industry. Most shoppers purchase fresh produce from outdoor carts and dry goods from family-owned "mom and pop" shops.

But, says another industry expert: "Tesco has moved into America, followed by India, when they don't yet have a real foothold in China. It feels like it is getting a bit dangerous. We have all sat and admired Tesco's execution of its strategy for the past 10 years. Will we be still saying that in 10 years' time?"