David Cameron warned families with incomes of more than £50,000 that they face losing tax credit benefits under a Conservative “government of thrift”.

The Tory leader also put public sector workers on notice that future pay and pensions deals would “reflect the realities of the economic situation” as he promised a new era of responsible politics.

“The days of easy money are over,” he told the party’s spring conference yesterday. “We have to replace Labour’s spendaholic government with a new government of thrift.”

Middle-class families could no longer expect taxpayer-funded handouts, he said. “When the age of austerity means that we must focus on the real priorities can we honestly say it’s right for people earning over £50,000 a year to get state benefits in the form of tax credits?”

About 130,000 households whose combined income is more than £50,000 qualify for tax credits of about £10 a week.

Mr Cameron said that people expected more than a “hair shirt and a stern lecture” and promised “massive culture change at every level of government, so the state is no longer casual, but careful, with public money”.

Technological advances would help a Conservative government to deliver services for a fraction of the cost once the state gave back control to individuals. He warned activists to expect a long, hard road. “We may not see the full fruits of our labours in the lifetime of our government,” he said, adding that party would be judged on whether it had dealt with the “debt crisis”.

During a question and answer session, Philip Hammond, the Shadow Chief Secretary, appeared to suggest that a Tory government would aim to almost halve Britain’s debt to below 40 per cent of the national wealth.

Mr Cameron dropped from his speech a promise that he would steer the country to “the sunshine on the other side”. Instead, he said: “If we stick together and tackle this crisis, our children and grandchildren will thank us for what we did for them and for our country.”

He promised that he would honour the three-year public sector pay deals agreed by Labour but warned that future pay deals would be “only as high as the country can responsibly afford”.

He said that investment in nurses, doctors, teachers and police was “money well spent” and attacked “public sector bureaucrats”. By publishing details of all public sector salaries over £150,000, he would “out” the mandarins who had been “getting rich at the taxpayer’s expense”.

The promise is part of his People’s Right to Know plan, which would also result in a Tory government publishing on the internet all government spending over £25,000.

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