British Prime Minister-designate Rishi Sunak's father-in-law and Indian billionaire businessman NR Narayana Murthy has said he is confident that his son-in-law will do the best for the people of the UK.

Sunak, 42, on Monday was elected as the new leader of the ruling Conservative Party and is all set to become Britain's first prime minister of Indian origin.

"Congratulations to Rishi. We are proud of him and we wish him success. We are confident he will do his best for the people of the United Kingdom," Narayana Murthy, the founder of Indian software behemoth Infosys, told the local media.

Sunak, the former British Chancellor, tied the knot with Narayana Murthy's daughter Akshata a leading fashion designer, in 2009. The couple, who met at Stanford University, has two daughters.

Akshata and Sunak are one of the wealthiest couples in Britain, with a combined fortune of 730 million pounds.

Akshata holds a 0.93% stake in Infosys, and her personal wealth hogged media limelight in the context of her claim of non-domiciled status in the UK.