On the eve of the announcement of the new Labour leader, David Cameron has launched his fiercest attack on the party since the general election, branding them "a clear threat to the security of British families".
The PM said that he watched the contest to succeed Ed Miliband with "bewilderment" and argued, whoever wins on Saturday, the party is "extreme" and has "completely vacated the intellectual playing field and no longer represents working people".
He said that the Labour leadership contest showed that the party had still failed to grasp the ideas that the national deficit needs to be cut and public services reformed.
"It's as if the financial crash, or the election for that matter, never happened".
Whoever wins the Labour leadership tomorrow, this is now a party that has completely vacated the intellectual playing field and no longer represents working people. It is arguing at the extremes of the debate, simply wedded to more spending, more borrowing, and more taxes.
Mr Cameron used speech in Leeds to try and win back some of the political centre ground previously staked out by New Labour, framing the Conservatives as the "progressive party".
The Prime Minister claims the Tory Government will pursue these goals by following the example of successful businesses, seeking new ways of doing things and delivering more for less in what he terms "a smarter state".
He countered the anti-austerity message of Labour frontrunner Jeremy Corbyn by arguing that the government reforms branded "cuts" are in fact examples of using new technology and innovative thinking to "deliver more for less", as successful businesses do.
Spreading opportunity, increasing social mobility, helping people get on - these aims run through this Government like letters through a stick of rock.