In a tweet before heading to the UK, PM Modi said, "I am hopeful this visit will strengthen economic ties between India and UK & bring more investment to India.#makeinindia"

Before the visit, the government eased foreign investment rules in 15 sectors in a major reforms measure to drum up investment and also counter allegations that the PM's reforms drive is slowing.

India and Britain could announce deals worth billions of dollars during the visit; India is keen to buy 20 more BAE Systems Hawk trainer aircraft for its armed forces, to be made in Bengaluru.

The Prime Minister's visit comes in the shadow of turmoil within the ruling BJP after its defeat in the Bihar election, its biggest political setback in 17 months in power. BJP veterans like LK Advani and Murli Manohar Joshi have gone public with their criticism of the party's leadership.

On his arrival in London, PM Modi will be welcomed with a Guard of Honour and after that, he will hold talks with Mr Cameron. Both prime ministers will also address a joint press conference.

PM Modi will also address the British Parliament before arriving at Chequers, the country home of Mr Cameron. The two are expected to have a joint yoga session there.

On Friday, PM Modi will have lunch with Queen Elizabeth at Buckingham Palace and then address the Indian community in a massive reception at Wembley. These events have become a staple of his foreign visits since his spectacular outing at New York's Madison Square Garden last year.

The mass rally and fireworks display at Wembley is being seen as the centerpiece of the three-day visit. The event will star more than 600 artists in an Olympic-style ceremony attended by over an audience of over 60,000. The welcome speech will be delivered by Mr Cameron, who has joked: "I sometimes wonder why I don't have the magical ability to bring 60,000 people of my city together at one place."

PM Modi's visit, the first by an Indian prime minister since 2006, follows Chinese President Xi Jinping's visit last month that yielded $62 billion of deals.