Gordon Brown has called for reformed global institutions to meet the challenges of a new century.
This could include a permanent seat for India on the UN security council, he said on the penultimate day of a visit to the country.
India has been calling for greater representation on the UN, along with Germany, Japan and Brazil, while modernisers say at least one African state should also be represented.
Britain has been sympathetic towards this argument, accepting that the UN security council is representative of the world that created it in 1948.
China, the US and Russia have traditionally been more resistant to extending the membership of the UN security council.
India is now on course to be the world's most populous country within a decade while it is already the second fastest growing global economy.
Speaking during the penultimate day of his tour of China and India, Mr Brown said he supported giving greater prominence to the world's largest democracy.
"The world is going to move very fast and there is no future for the big economic events which meet with just five, six or eight powers which doesn't include India, which is growing so fast," the Guardian reported him as saying.
The prime minister continued: "I would like to see India as a member of the UN security council. I want the G8 plus 5 [Brazil, China, India, Mexico and South Africa] to meet regularly and that should include the full role India should have in the discussion of global economic affairs.
"I look forward to extending the partnership of equals over the next decade."
Mr Brown also called for reform of the World Bank, including a dedicated fund to fight global warming.
He told crowds in India it was time to build "a new global society".