The next time somebody tries to argue that nobody could have foreseen just how bad the banking crisis could get for Ireland, remember Morgan Kelly. He is the coldly pessimistic UCD economist who predicted in 2007, based on evidence from property crashes going back to the 1970s, that Irish property values were heading for a catastrophic 60% drop from peak prices. And that was the conservative estimate.

Today he looks like a sage, but at the time Kelly's analysis was derided by the government and financial industry alike. This was, after all, back when Bertie Ahern was recommending suicide for those who questioned Fianna Fáil's economic doctrine.

In the past three years Kelly has opposed the bank guarantee, warned against nationalising Anglo Irish Bank and argued that Nama was the wrong way to go. He said all of these policy steps would foist enormous costs onto the taxpayer and risk national bankruptcy – and so it has come to pass.

But Kelly is no longer a lone dissident. He has been joined by a group of commentators who have consistently challenged the official line of the Department of Finance, the banks and the stockbrokers: academic economists Karl Whelan, Brian Lucey and Constantin Gurdgiev, retired banker Peter Mathews, and financial analyst Paul Sommerville, to name the more prominent voices.

These are the people who got it right, the ones who saw the calamity for what it was and tried to get the measure of it. Though very visible in the media, they have been largely ignored by a path-dependent government which is still relying on a coterie of investment banks, accountants and law firms for advice.

"When I first saw Morgan Kelly's research, I said, 'This can't be right, can it?" said Brian Lucey, associate professor of finance at Trinity College Dublin. "But he sent me the data and I couldn't find much wrong with it. The scales fell from my eyes: we were in for a mighty thump."

Lucey was originally in the 'soft landing' camp, believing Ireland's downward adjustment from peak prices would be gradual and minimal. Kelly's work and an unravelling housing market changed his mind. He went off, did his research, and eventually concluded the domestic banking sector was facing about €60bn in losses – a figure official estimates are now approaching following finance minister Brian Lenihan's upward revisions to €50bn-plus early this month.

"The government is converging rapidly with reality but we've wasted two years getting an honest appraisal," said Lucey. "They had plenty of advice available to them. Unfortunately they did the financial equivalent of trying to defy gravity."

Lucey and his academic colleagues Karl Whelan and Constantin Gurdgiev have formally briefed every political party on the crisis – bar Fianna Fáil. Lucey said it was a "terrible indictment" of the Department of Finance that critics like them were not brought on board.

"At all stages critics were willing to talk," he said. "The government had ideological preconceptions about the way they were going to solve this."

The eventual solution – Nama – proved highly controversial, prompting Lucey, Whelan, Gurdgiev and dozens of other economists to publicly oppose the agency in spring 2009.

Even before Nama was formally unveiled, Whelan, a professor of economics at UCD, raised doubts about the efficacy of a 'bad bank' approach to dealing with unpaid property loans. His concerns turned out to be rather prescient: "It is questionable whether the bad bank proposal could achieve its goal of properly recapitalising private sector banks. There may be limits on the price the government can pay for impaired property loans under EU state aid rules... It is easy to imagine a scenario in which the Irish banks struggled on with weak capital bases even after a bad bank scheme has been put in place."

Recognising this danger, once Nama was announced Whelan and his cohort proposed temporary nationalisation of the banks covered under the guarantee scheme to fast-track the transfer of assets to the agency. They met serious PR pushback from the government and financial sector, which characterised their plan as politically and economically daft.

"They imagined nationalising AIB and Bank of Ireland (BoI) was the worst thing that could happen, but they didn't realise how bad things could get," said Whelan. "I'm not convinced that we have seen the end of the loan losses at AIB and BoI. With more write-downs to come on its non-Nama loans, BoI may also end up in majority state ownership."

If Whelan's prediction comes to pass, every single bank in Nama will have effectively been nationalised. In other words, the government and banks took the long, painful road to Whelan's quick and easy solution from early 2009.

"Experience from previous banking crises shows that bankers always try to save their own skins by understating the scale of the problems," said Whelan. "The government also didn't seem too interested in really getting to the bottom of the scale of the problem. Probably they felt they needed an honest assessment of the state of the banks like a hole in the head."

Retired banker turned finance pundit Peter Mathews is slightly less diplomatic in his characterisation of the government's handling of the crisis, describing it as "questionable, wrong, misleading, dishonest – nobody is covered in honour". Mathews has been banging on the doors of officialdom for more than a year, trying to get the government's ear and insisting that the bank losses were going to be enormous. But he was told the Department of Finance was too busy to see him.

His most recent figure is €66bn, totted up on a single sheet for clarity. That's still more than 25% higher than what Lenihan believes, but Mathews has form: last March, when the Financial Regulator put AIB's capital needs at €7.4bn, he said it wouldn't be less than €10bn. AIB's revised figure – the one that will see it 90% owned by the state – is €10.4bn.

"In the last couple of months there has been a reluctant acknowledgment that the figures were right, a silent, resentful acknowledgement," he said. "This time last year we were under the steamroller propaganda machine which was saying 'Nama is the only game in town'."

Constantin Gurdgiev, lecturer in finance at Trinity, is somewhat less gracious in victory, accusing the government of being "deeply in a bunker".

"We are hearing nonsensical statements still from our finance minister," said Gurdgiev. "For instance that we are not in a double-dip recession when the growth figures clearly show that we are."

Ireland has moved past the banking crisis into a full-blown sovereign crisis because of the government's reluctance to face reality, he said. Having taken on so much debt to fix the banks, the government may have dug a hole from which the country cannot emerge.

"The current levels of debt require 4.5% or 5% of growth a year," he said. "This is a structural issue. Path dependence puts us in a situation where we are likely to face not just a solvency crisis, but a liquidity crisis in the next six months."