DAVID Cameron has failed to close down a row over whether or not a future Conservative government would reduce child benefit despite suggesting there would be no reductions in the state handout, if he won power next week.

Following his failure to be categoric about future Tory plans during the BBC Question Time leaders' cross-examination, which caused Ed Miliband to insist the issue remained on the ballot paper, the Prime Minister sought to end the continuing row.

Stressing how finding savings in the £200 billion-plus annual welfare bill were needed to protect the NHS and other key budgets, Mr Cameron - using the present tense - said: "Let me be absolutely clear; we are not cutting child benefit, we are keeping child benefit."

Noting how he had already announced plans to continue freezing child benefit for two more years, he stressed: "But it is an absolutely crucial benefit and, with me as Prime Minister, it stays."

Pressed on whether that meant there would be no changes to the higher rate of benefit for the first-born child or means-testing, the Tory leader replied: "We had those proposals put to us, we rejected them; they are not right. We keep child benefit, we don't cut child benefit."

The row erupted on Wednesday when Danny Alexander, the Liberal Democrat Chief Secretary to the Treasury, leaked so-called Tory plans that were circulated to the four most senior Cabinet ministers in a paper three years ago. Proposals floated also included removing child benefit from 16 to 19-year-olds as well as means-testing the payment.

But while the Tory leadership insisted it had rejected the "set" of proposals, fears persisted, particularly after Mr Cameron on the BBC programme repeatedly refused to rule cuts out categorically.

But yesterday he told ITV News: "We are not cutting child benefit, we are keeping child benefit...It is an absolutely crucial benefit and with me as prime minister, it stays."

However, his critics insist this still gives Mr Cameron wriggle room to make some changes that could affect payments. Labour appears adamant to keep up the attacks.

After a campaign speech in south-west England, Mr Miliband tweeted a picture of himself, saying: "I've just finished speaking to people in Bristol about our commitment to protect child benefit and the Tories' plan to cut it."

Ed Balls also waded in, saying: "After days of weasel words and prevarication David Cameron is still failing to rule out cutting child benefit and tax credits again. All he has said again is he won't abolish child benefit but he won't deny he plans to cut it or take it away from millions of families. Everyone knows it's impossible for the Tories to achieve their £12bn of cuts to social security without hitting family budgets hard."

The Shadow Chancellor added: "Child benefit and tax credits are now on the ballot paper next week. While Labour will protect them, the whole country now knows the Tories will cut them again."

Earlier this week, the Institute for Fiscal Studies said of the Tories' planned £12bn welfare cuts: "It is hard to see how such savings could be achieved without sharp reductions in the generosity of, or eligibility to, one or more of child benefit, disability benefits, housing benefit and tax credits."