Indian PM Modi arrives in UK for three day visit
India's Prime Minister Narendra Modi has arrived in the UK for a three day visit as a guest of his British counterpart, David Cameron.
The first day of the visit will be marked by a Red Arrows flypast before Mr Modi makes a speech to Parliament.
Also during the trip, he will meet the Queen, visit a statue of Mahatma Gandhi and address crowds at Wembley Stadium.
Mr Cameron said the visit marked "a historic opportunity" for Britain and India to help each other prosper.
"It's an opportunity for two countries, tied by history, people and values, to work together to overcome the biggest challenges of our age," Mr Cameron said.
"Prime Minister Modi and I intend to grab that opportunity with both hands."
Mr Modi said the aim of the visit was to strengthen "co-operation with a traditional friend".
On arrival, he tweeted: "Reached London. India-UK ties will receive a great impetus. Will attend a wide range of programmes in UK."
BBC News correspondent Christian Fraser said India's growing economy was "crucially important to British industry and trade".
"We're told that around £10bn worth of trade deals will be signed over the course of the next two days," he added.
Indian businesses in the UK
110,000
people are employed by Indian companies operating in the UK
- 13 Indian companies each employ more than 1,000 people in the UK
- 65,000 people work for Tata Group, which owns 5 of those 13 companies
- 28,000 of those work for Tata Motors, which owns Jaguar Land Rover
Downing Street protests
The visit comes at an unsettled time in India, where Mr Modi's Hindu-nationalist party lost a recent regional election.
The Bharatiya Janata Party (BJP) suffered the defeat in the northern Indian state of Bihar, amid concerns over a rise in religious intolerance in India.
His supporters will hope his visit will help him spring back from that defeat.
Campaigners from the UK-based Awaaz Network say they are against Mr Modi's "violent authoritarian agenda that seeks to undermine India's democratic and secular fabric".
Dozens of writers have signed a letter to Mr Cameron, asking him to urge Mr Modi to "provide better protection for writers, artists and other critical voices and ensure that freedom of speech is safeguarded" in India.
Analysis
By Justin Rowlatt, BBC South Asia correspondent
Mr Modi sells himself as a no-nonsense technocrat who transformed his home state, Gujarat, into an economic powerhouse.
He won a landslide a year and a half ago on the promise that he would do the same for the entire country.
He has suffered some setbacks. Many of his reforms have been blocked in parliament but India is still a formidable economic force, growing at some 7% a year.
Mr Cameron told Mr Modi last year that "relations with India are at the top of the priorities of UK's foreign policy".
And he has put in the air miles to prove he is serious, visiting India three times since he came to power.
Asked about criticism of Mr Modi, Lord Bilimoria, a cross-bench peer who chairs the UK India Business Council, said current changes in India were a "very positive story".
He said Mr Modi faced "huge challenges" and he must bring about "inclusive growth" to succeed.
'Massive market opportunities'
Kilbinder Dosanjh, a specialist on India's political economy at the Eurasia Group, said the UK was seen as "quite secondary" among the countries India wanted to build ties with.
He said Mr Modi wanted expertise from Japan and Germany to build infrastructure including roads and railways, and France had also been building a relationship with India.
But he said India's rapidly growing middle class provided "massive market opportunities" for the UK.
Mr Modi's arrival in London will be marked with a flypast by the RAF's aerobatic team, the Red Arrows, over the House of Commons.
During the visit, Mr Modi will stay at Chequers, Mr Cameron's official country retreat in Buckinghamshire.
On Friday, Mr Modi will speak, mainly in Hindi, to some 60,000 people due at the Wembley event, which is expected to be a celebration of the Indian diaspora's contribution to the British economy.
Organisers have promised an Olympic-style reception for the Indian prime minister.
He will also visit the statue of Indian statesman Mahatma Gandhi, which stands alongside those of British prime ministers Benjamin Disraeli and Sir Winston Churchill in London's Parliament Square.