World leaders have sent incoming British prime minister Rishi Sunak messages of goodwill, led by India's Prime Minister Narendra Modi.
Mr Sunak is Britain's first Hindu prime minister and also its first of Asian descent.
Many in India lauded Mr Sunak’s success as the country celebrates Diwali, one of the most important Hindu festivals.
“Warmest congratulations, Rishi Sunak!” Mr Modi said. “As you become UK PM, I look forward to working closely together on global issues and implementing road map 2030.
“Special Diwali wishes to the ‘living bridge’ of UK Indians, as we transform our historic ties into a modern partnership.”
US President Joe Biden said at a White House Diwali celebration on Monday that Mr Sunak's appointment would be a "groundbreaking milestone ... it matters".
Monday, October 24, was also the deadline set by then-prime minister Boris Johnson to sign a free trade deal with India.
Earlier this month, Downing Street said there was no rush for Britain to finalise an agreement with New Delhi amid reports that talks with the Indian government were close to collapse.
But this did not stem the flow of congratulations that poured in from prominent Indians.
Delhi businessman Manoj Garg said: “It is a moment of pride for India that the country which ruled us for many years has now a prime minister of Indian heritage.”
Politician Raghav Chadha tweeted: “Today, as India celebrates Diwali in its 75th year as an independent nation, the UK gets an Indian-origin prime minister. History comes full circle.”
Others praised Mr Sunak's being a “proud Hindu”, saying he did not shy away from embracing his faith and culture.
Mr Sunak is married to Akshata Murthy, whose father is Indian billionaire N R Narayana Murthy, founder of tech company Infosys.
Roberta Metsola, president of the European Parliament, also congratulated Mr Sunak and emphasised the need for “a strong and constructive relationship with the UK”.
“Congratulations to the next prime minister of the United Kingdom, Rishi Sunak,” she said.
“At a time of enormous challenges, Europe needs political and economic stability. Our core interests remain the same.”
European Council President Charles Michel tweeted his congratulations.
“Working together is the only way to face common challenges … and bringing stability is key to overcoming them,” Mr Michel said.
Irish Deputy Prime Minister Leo Varadkar also sent his congratulations to Mr Sunak.
