Cameron: Corbyn's Labor 'A Security Threat'

Mr Corbyn stormed to an overwhelming victory in the party's leadership race on his anti-war, anti-austerity platform.

But the Prime Minister warned in a tweet Sunday that "The Labor Party is now a threat to our national security, our economic security and your family's security," Sky News reported. 

Before the veteran MP's triumph was announced on Saturday, Mr Cameron had warned he would be bad for the country.

He said Mr Corbyn would break a valuable consensus between the main parties on issues such as nationalization, nuclear weapons, taxation and union laws.

"The country is stronger when you have shared objectives rather than when you've got someone who wants to take us back to the days of Michael Foot and Arthur Scargill," he said.

Downing Street said Mr Cameron phoned his new adversary to congratulate him on Saturday.

The pair are due to face off for the first time at PMQs on Wednesday.

Mr Corbyn has appealed to supporters to suggest what they would like him to ask Mr Cameron at the weekly Commons clash.

"Help me be your representative. When I stand at the despatch box for Prime Minister's Questions on Wednesday, I want to be your voice," he wrote in an email.

The new leader is currently putting together his first shadow cabinet in the face of deep divisions in the party.

Six shadow cabinet ministers have so far resigned, with others also tipped to go.

He and his new team will then work on trying to unite the party behind his policies.

Mr Corbyn says his win - with 59.5% of the more than 400,000 votes - represented "a huge mandate for a new democracy in the party".

"I think the membership and supporters will want and expect members of the parliamentary party to cooperate with the new leader and let us develop an effective strategy for opposing the Tories on the issues I outlined in my speech: welfare reform, trade unions, budget and so on," he told the Observer.