David Cameron
Cameron launched the first of six theme at the heart of the Conservative Party's general election manifestoReuters

The prime minister has launched the first of six themes at the heart of the Conservative Party manifesto ahead of the 2015 General Election, warning this generation of voters not to leave a "legacy of debt" to their children.

David Cameron promised a Tory government would deal with the deficit to make sure the UK is "a country that lives within its means once again".

The Conservative leader claimed it was vital we do not leave a "crippling legacy of debt" our children and grandchildren could never hope to repay.

"When you look at the children you love, do you want to land them with a legacy of huge debts?" he asked.

"Do you want to limit their future, to make life more difficult for their generation, because we refuse to do the right thing in our generation?

"I say we have a responsibility to act. We can get Britain back to living within our means in a way that is fair and sensible and secure."

Cameron made a number of pledges in a bid to make good on his promise, including to run a surplus and, among other things, control the welfare budget so "we save money and reward work".

The prime minister warned "the writing is on the wall" if the government did not deal with the £90bn ($136bn, €115bn) deficit with spending cuts.

Cameron also promised he would increase NHS spending and "not a penny" would be cut from the health service's budget.

But Labour leader Ed Miliband hit back at the Conservatives and argued that Cameron and the Chancellor George Osborne had "failed" on the deficit because they have "failed" on living standards.

"Unless we have higher wages and living standards, we won't get the revenue to reduce the deficit," he said.

"Their plan will keep failing on living standards and therefore keep failing on the deficit.

"And now they want to go even further: back to the 1930s on public spending."

Miliband added: "No wonder David Cameron has gone from saying the NHS were the three most important letters to him to the health service becoming the subject that dare not speak its name."

The exchange comes less than four months before the general election in May.

The latest poll from YouGov for The Sunday Times put the two parties neck-and-neck (32% vs 32%).