The London-based Srichand and Gopichand Hinduja, who have a fortune of 11.9 billion pounds - "up by an astonishing 1.3 billion pounds in the past year", edged out steel tycoon Lakshmi N Mittal and Russian magnate Alisher Usmanov, according to the 'Sunday Times Super-Rich List' made public on Sunday.
The Hinduja brothers, who run the multinational Hinduja Group conglomerate with interests across automotive, real estate and oil, moved up from third position last year to top the UK's billionaire charts this year.
The list - a full version of which will be released next Sunday - also includes NRI industrialists such as Lakshmi Mittal and family, Prakash Lohia, Lord Swraj Paul and family, Anil Agarwal and Ajay Kalsi and family among the city's 72 billionaires.
Mittal also edged one position upwards to the third rank with 10.25 billion pounds even as Russian magnate Alisher Usmanov, who topped the list till last year, fell to the second place.
"Last year, the Hindujas sold a 49 per cent stake in a Saudi Arabian lubricants maker, Petromin, for more than 200 million pounds.
Property investments in India have added 200 million pounds. The family's IndusInd bank is capitalised at about 2.7 billion pounds.
In Britain, Hinduja Automotive turned over about 1.5 billion pounds in 2012-13," the newspaper said.
In reference to the Kolkata-based Mittal, the newspaper highlighted a final bounce in fortunes after a few years of dip.
"After a tough few years in the steel industry, Mittal is seeing a glimmer of light. Arcelor Mittal shares have recovered, making his stake worth 6.65 billion pounds - up 700 million pounds in a year," it said.
Mittal's brother-in-law India-born textiles and plastics tycoon Lohia is ranked as Britain's 46th richest man with around 2.11 billion pounds.
Leading NRI industrialist and Caparo chief Lord Swraj Paul is ranked Britain's 48th richest, with an estimated wealth worth around 2 billion pounds.
"The 83-year-old came to Britain from India in 1966 to seek treatment for his daughter's leukaemia.
He stayed after her death and founded steel manufacturer Caparo, which made more than 62 million pounds profit in 2013.
The company has been restructured, with its American and Indian businesses worth 1.6 billion pounds," the newspaper said.
Hiranandani bros among Singapore's richest property tycoons
Dilip Shanghvi among Asia's richest self-made billionaires
Can you invest and grow rich like Warren Buffett?
Hindujas are wealthiest Asians in UK
Lord Paul's mantra to stamp out corruption