Prime Minister Narendra Modi has arrived here to attend the Commonwealth Heads of Government Meeting (CHOGM).
The PM was received at the Heathrow airport on Tuesday by UK Foreign Secretary Boris Johnson.
In UK, the PM will hold a bilateral meeting with British Prime Minister Theresa May at 10 Downing Street and attend the CHOGM.
Mr Modi last visited the UK in November 2015.
During his visit, the Prime Minister will be focusing on enhancing India-UK partnership in the areas healthcare, innovation, digitisation, electric mobility, clean energy, and cyber security.
The PM will also call on Queen Elizabeth.
He will also interact briefly with CEOs of the two nations.
He will launch an Ayurveda Centre of Excellence in London, and welcome the UK into the International Solar Alliance, as its newest member.
On April 19 and 20, the PM will also participate in the CHOGM being hosted by the United Kingdom which will take over as the new Chair-in-Office of the Commonwealth from Malta.