U.K. Prime Minister David Cameron delivers a speech on June 7 in London on the upcoming Brexit referendum. He has warned state pension increases and ring-fenced health spending could be at risk if the U.K. leaves the EU.

British state pension increases and ring-fenced heath spending would be in danger if voters chose the Brexit, Prime Minister David Cameron warned in a Sunday interview with the Observer.

As a poll showed that the majority of British people were in favor of leaving the European Union (EU) - a departure known as the Brexit - Cameron said that voters needed to face the "cold reality" of the austerity that would be required if the U.K. was outside the EU.



He referred to research by the Institute of Fiscal Studies and the National Institute for Economic and Social Policy that showed the Brexit would create a black hole of up to 40 billion pounds in U.K. public finances by 2020.

"You would have to start cutting things that people really value, whether it is the money going to the NHS [the state health service] or whether it is support for our pension system, and that could mean reviewing the triple lock," Cameron said in an exclusive interview with the Observer, published on Sunday.

The "triple lock" referred to a guarantee that the state pension would rise annually in line with whichever was higher: earnings, inflation or 2.5 percent.

To read the full Observer report, click here.