Ed Miliband has made a direct pitch for the support of disaffected “one nation” Tories, insisting that he is on “the centre ground of politics” and would save the country from David Cameron’s rightwing, anti-EU agenda.

In an interview with the Observer, two-and-a-half weeks before polling day, Miliband reaches out to moderate Tories, saying Labour is now a party of “fiscal discipline” and social conscience that would tackle inequality and keep the UK firmly at the heart of Europe.

Ed Miliband interview: ‘I want to reach out to Tory voters’ Read more

The Labour leader says: “I am a politician of the left, but I am positioned where the mainstream of politics is positioned. I am on the centre ground of politics.” By contrast, he describes Cameron as “ideologically beached” and with no answers about how to tackle inequality.

Appealing directly to Conservatives who want to build a fairer society, he says: “I want to reach out to Tory voters, to Liberal Democrat voters, to Ukip voters, to non-voters … to people who feel that David Cameron can’t answer the challenge of our time, who worry about our place in the European Union, who really think to themselves, ‘we can do a lot better as a country’.”

Asked what he could offer Conservatives worried about the rightward drift of their party, he says: “Who is going to stand up to tax avoidance? Who is going to stand up to energy companies? Who is going to stand up to banks? That is absolutely something I think will appeal to Tory voters.”

Miliband’s appeal is partly designed to counter Tory claims that he would team up with the SNP in a leftwing coalition in the event of another hung parliament after 7 May.

But Labour strategists also believe Miliband is succeeding in building his reputation in the country during the current election campaign and is appealing to centre-ground voters who had believed, beforehand, that he was not prime ministerial and was too leftwing.

In the interview, Miliband says the past 10 days of the campaign have seen the Tories become the “incredible party”, whose unfunded promises on everything from the NHS to transport and housing have turned them into the party of “funny money”.

He showers praise on his shadow chancellor, Ed Balls, as the man who has repositioned Labour as a party of fiscal rectitude and comes close to anointing him chancellor if Labour wins on 7 May. “He’s incredibly well qualified for the job, yes,” he says.

Ahead of a week in which it wants to focus on its plans for the NHS, Labour will release official figures that it claims show the government intends to cut the number of nurses by 2,000 in the first year of the next parliament, despite having promised recently to pump an extra £8bn into healthcare by 2020.

Miliband will seek to contrast his own party’s fully costed plans for the NHS with unfunded Tory plans, when he announces how Labour would guarantee to push an emergency stream of funding into the health service in the first year of a Labour government.

Andy Burnham, the shadow health secretary, will say plans to cut nursing numbers show the Tory promises on extra funding will pass their sell-by date on 7 May. He will cite figures in Health Education England’s (HEE) Workforce Plan for England 2015/16, which he says shows the service will be employing nearly 2,000 fewer nurses over the next four years – for reasons “mainly driven by affordability”.

“These plans show the NHS simply cannot take five more years of David Cameron. He is saying one thing in public, but drawing up plans in secret to cut nurses. It is clear the Tory NHS promises have an expiry date stamped on them,” says Burnham. “Hospitals are already at their limits and staff are working wonders, but this plan will push them over the edge. It proves David Cameron’s promises on the NHS can’t be trusted.

“Labour has set out a better plan to invest £2.5bn extra each year, on top of Tory spending plans, paid for by a mansion tax on homes worth £2m, to fund 20,000 more nurses and 8,000 more GPs.”

Conservatives take four-point lead over Labour in Opinium/Observer poll Read more

While Labour MPs and activists have been buoyed by the way Miliband has performed in the early part of the election campaign, the latest Opinium poll for the Observer puts the Tories on 36%, four points ahead of Labour, which is on 32%. Ukip is on 13%, the Lib Dems 8% and the Greens 5%. However, a YouGov poll for the Sunday Times has Labour on 36% – three points ahead of the Tories – with the other main parties matching the Opinium poll. Most polls in the past week have put the two main parties neck-and-neck, suggesting the country is heading for another hung parliament.

While Miliband says he is “optimistic” that Labour can win the election as the largest party and hopes to win a majority, many senior Labour figures still believe it will be a long haul.

Campaigning in north London last week, former Labour home secretary Alan Johnson said the party had failed to combat Tory claims that it had been responsible for the economic crash of 2008. “This is where we should have done more; on this big lie of Labour’s economic failure,” Johnson said. “There is no soundbite that we have got to equal the claim that we maxed out on your credit card … I think we need to do more on that. I was pleased Ed put the economy on the front of the manifesto. It gives us a chance to say that we can’t ignore the financial deficit and also explain how the financial deficit came to be there.”

Asked if it was too late to address the issue now, Johnson added: “That’s my frustration. As Lynton Crosby [David Cameron’s chief election strategist] said, you don’t fatten the pig on market day.”