David Cameron has announced new ventures worth more than £9 billion between India and the UK.
Speaking at a joint press conference with India's Prime Minister Narendra Modi, Mr Cameron said it was "a real opportunity to open a new chapter in the relationship between our two countries".
He also said the UK firmly supports the notion of a permanent seat for India on UN security council.
Mr Modi, who is the first Indian Prime Minister to visit Britain in almost a decade, also confirmed he has signed civil nuclear agreement with Britain.
His three-day trip will include a meeting with the Queen and a rally at Wembley Stadium on Friday, where 60,000 mostly British-Indian ticket-holders will be in attendance.
Hundreds of protesters gathered outside Downing Street ahead of Narendra Modi's arrival on Thursday.
Messages on the banners of those protesting against his presence included "Modi not welcome", "Stop religious persecution", and "Remove illegal blockade in Nepal".
More than 200 writers, including Ian McEwan, Salman Rushdie and Val McDermid, have written an open letter to David Cameron to raise concerns about freedom of expression in India during his talks with Mr Modi.
A number of pro-Modi demonstrators also held banners and chanted outside Downing Streeet ahead of the visit.
David Cameron has welcomed Prime Minister Narendra Modi to Downing Street as the Indian leader begins a three-day visit to the UK.
The two leaders shook hands on the doorstep of Number 10 before heading inside for talks.
Indian Prime Minister Narendra Modi has arrived in the UK for a three-day visit.
Mr Modi was greeted at Heathrow Airport on Thursday morning.
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Sainsbury's underlying pre-tax profit was down 17.9% to £308 million, results from the supermarket revealed on Wednesday.
Like-for-like sales were down 1.6% in the 28 weeks to September 26, while underlying group sales were down 2% to £13.6 million, compared to £13.9m in the same period last year.
Sainsbury's chief executive Mike Coupe said: “The grocery retail marketplace remains challenging but Sainsbury’s is a great business, run by an experienced management team, supported by talented colleagues and strong values.
"I am confident we are making progress and we are looking forward to a successful Christmas, offering our customers fantastic products and great value."
Police have warned shops to ensure they have properly thought-out security arrangements for the Black Friday sales later this month.Read the full story ›