Cameron was taking questions from the audience last night as part of a special BBC 'Question Time' show when he said, "The rise of countries like India and China...[means we have] big economies that we need to trade with more. But European trade and European economies have grown a great amount since we joined in 1972".
He said Britain could "do more with India" but not at the expense of cutting itself off from the EU. Responding to a question on why the share of EU world trade had dropped from 20 to 15 percent, he said, "It has dropped as a share of the total but as an entity it has increased".
Cameron also said that about 80 percent of Britain's economy is services, things like insurance and banking and architecture and sales and advertising etc.
"We sell more in services today to Luxembourg than we do to the whole of India. Of course, we need to do better with India; we need a trade deal with India. But the idea that we should cut ourselves off from our main market, I think is economic madness. We need to work to succeed in our main market and then open up the other markets," he said.
About 45 percent of the UK's exports go to EU with its exports to the bloc accounting for 227 billion pounds and imports accounting for 288 billion pounds in 2014.
The debate for Britain's future with the 28-member economic bloc enters its final stages this week with just three days to go before the crucial referendum.
With opinion polls reflecting a very close contest between the side in favour to remain and those in favour of an exit, so-called Brexit, some of the UK's senior-most entrepreneurs and professionals today came out strongly for remain.
Ken Gregor, Chief Financial Officer (CFO) of Tata Motors owned Jaguar Land Rover (JLR), said: "Remaining in the EU–our largest market– will increase Jaguar Land Rover's chances to grow, create jobs and attract investment in future technologies."
"Our European supply chain has been fundamental in helping us to meet customer expectations worldwide and achieve sustainable, profitable growth," Gregor said.
He joined Britain's car industry trade body, the Society of Motor Manufacturers and Traders' (SMMT), to warn leaving the EU would increase costs and threaten jobs.

Latest News from World News Desk