Mr Cameron made the announcement at a cabinet meeting on Saturday morning after leaving Brussels with what he described as a "historic" deal on the UK's future relationship with Europe.

Leaving the EU, Cameron said, would be a "leap in the dark", potentially threatening Britain's economic and national security.

Time of uncertainty

"Those who want to leave Europe cannot tell you if British businesses would be able to access Europe's free trade single market, or if working people's jobs are safe, or how much prices would rise.

"All they're offering is a risk at a time of uncertainty − a leap in the dark," he said.

While in Brussels, Cameron made agreements over welfare payments to migrants, Britain's right to opt out of the eurozone, and a promise the UK would have stronger sovereign control over laws made in Brussels.

He urged voters to back these reforms on 23 June.

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