DAVID Cameron has told Hampshire activists that leaving the EU would be the "self-destruct option" for Britain.

Speaking at the B&Q HQ in Chandler's Ford, the Prime Minister said a Leave vote would create the world's first "DIY recession" as the country inflicted economic harm on itself just as it was recovering from the crash of 2008.

And he said the threat to families' financial security and the nation's economy meant that a Remain vote was the "moral" choice in the referendum, exactly a month away on June 23.

It came as the Treasury published an analysis claiming that Brexit would plunge the country into a year-long recession and cost as many as 820,000 jobs.

Mr Cameron and Mr Osborne stayed briefly to take questions from the audience and media but left before many had got their say.

One who did was the firm's retail director Damien McGloughlin, who asked the Prime Minister: "Do you believe there's enough un-biased and un-complicated information for the public to make their decision?"

Mr Cameron replied: "Yes. It's a very big democratic debate.

"We've had opinions from all sorts of people."

Staff were told afterwards they would be unable to speak to the media.

The two men used the building as a platform to unveil a flagship new Treasury report laying bare the potential impact of a Brexit and its immediate short term impact on the economy, growth, jobs, trade, house prices and everyday family life.

Hundreds of staff crowded into the company's atrium packed on seating in the entrance and lining two tiers of balconies overhead to listen intently to the two most powerful men in Britain.

Excitement had been building throughout the morning with security tight at the headquarters and television crews and satellite van intently gathering at the entrance.

Staff excitedly crowded into the building clutching phones and waiting to catch a glimpse of the two men.

A hush sounded over the audience as both men arrived to launch speeches on their fears for Brexit and exclusively reveal the document "HM Treasury analysis: the immediate economic impact of leaving the EU".

New Treasury analysis of the short-term impact of withdrawal from the EU suggested that between 520,000 and 820,000 jobs would be lost, while house prices would fall by between 10% and 18%.

Public sector borrowing would rocket by between £24 billion and £39 billion, said the report.

But prominent Vote Leave campaigner Iain Duncan Smith said the warning "should not be believed by anyone" as it was "not an honest assessment but a deeply biased view of the future".

Mr Cameron said Britain was now "back on the right track" after the financial crisis, and urged voters not to put that at risk.

"As the Bank of England has said and the IMF has underlined, and the Treasury has now confirmed, the shock to our economy after leaving Europe would tip the country into recession," he said.

"This could be, for the first time in history, a recession brought on ourselves. As I stand here in B&Q, it would be a DIY recession."