Leader says that if Labour wins the election it will cut deficit every year while securing the future of the NHS

Labour has taken the symbolic decision to make the first of five election pledges a commitment to cut the deficit year on year, but he refused to give “an arbitrary date” by which it will be achieved – except to promise it will be as soon as possible in the next parliament.

Ed Miliband, in a keynote speech, gave himself flexibility by stressing that the pledge applied to the current deficit and that borrowing for capital investment would be treated differently. But he said there would be no pledges in the manifesto that would require extra capital spending beyond that set out in the autumn statement .

His willingness to talk about the deficit, after failing to do so in his Labour conference speech, will be welcomed by those in the party who believe it is a precondition for Labour receiving a wider hearing. But Miliband has to tread a fine line, since there is also a constituency of voters who appear to be defecting from mainstream parties on the basis that they are insufficiently radical.

Announcing the party’s first election pledge, the Labour leader said: “We will build a strong economic foundation and balance the books. We will cut the deficit every year while securing the future of the NHS. And none of our manifesto commitments will require additional borrowing.” He also said that the party’s department-by-department, zero-based review had found £500m in efficiency savings.

Miliband repeated the pledge made by the shadow chancellor, Ed Balls, in the Guardian at the weekend that he would cut the current deficit year on year until it was in balance, but insisted he would not set an arbitrary date for when this could be achieved.

The speech was also designed to portray the chancellor’s autumn statement as extreme, for forecasting an overall surplus of £23bn by 2019-20 and overall spending as a proportion of GDP falling to its lowest level for 80 years, at 35% of GDP. Miliband said this would lead to the disintegration of public services, and vowed Labour was now in a battle for the soul of the country. He said the Tory cuts were the equivalent of more than the whole schools budget, or three times the budget for social care.

He effectively ruled out Labour increasing VAT and refused to say if it would vote for the government’s charter of fiscal responsibility if, as expected, it called for the structural current deficit to be eliminated by 2017-18.

He would not say what he regarded as the right level of public spending as a proportion of GDP.

He refused to give further details of cuts and rejected the idea of a shadow budget, explaining: “If we start picking things out of the air without having done that work, without having gone into the departments and found how we make these changes, how we make these reductions in the most sensible way, then they won’t be the most sensible changes for the country.”

Asked about a possible VAT rise, he said: “I would steer you well away from any Labour government raising VAT. It hasn’t happened in the past, so I don’t think it’s going to happen in the future.”

He said: “There is a lesson from this parliament about the huge uncertainty there is around deficit reduction. The easy thing for politicians is to claim great certainty when there is not. The right thing to do is to set a clear objective with a realistic destination – balancing the books and the debt falling as soon as possible in the next parliament – and this is what we have done. Nothing does more to undermine credibility than setting an objective and failing to meet it.”

His words on borrowing – although carefully couched – do give him some flexibility. Labour has a rule that debt will fall, while the Tories have an investment rule to protect capital spending as a percentage of GDP, a formulation that gives Labour greater flexibility.

Carl Emmerson of the Institute for Fiscal Studies said the formulation gave Labour “a lot of wriggle room”, since Osborne planned to reach a £23bn overall surplus in 2019-20 and the Tories had plans for investment of £27bn. He added that the size of government would return to the level of the 1930s and late 1990s, but this would not mean living standards falling to that level.

The chief secretary to the Treasury, Danny Alexander, said the Labour plan meant a slow, relentless grind of difficult decisions, since it might not reach current deficit balance until the end of the parliament, instead of 2017-18 in the Lib Dem plan.

Miliband was asked to sum up his promise to Britain in eight words and immediately came up with an 10-word answer: “A country that works for you, not the privileged few.”