When voters choose the next government they will be participating in “the defining election of my generation,” George Osborne, the 37-year-old shadow chancellor, said on Thursday.

The contest will pitch the Conservatives’ new “austerity politics” against Labour’s track record of high spending. The public has for more than a decade voted against the alleged threat that the Tories would cut front-line public services. But Mr Osborne said he was sure voters were now prepared to hear what will be a tough manifesto message on the need for spending restraint.