SEÁN QUINN conceded yesterday that the biggest mistake he had made was chasing his investment losses as shares in Anglo Irish Bank began to fall in 2007.

As his son Seán jnr acclimatised to life in prison, the former billionaire said he had “foolishly” pursued his money – invested in Anglo shares through highly leveraged contracts for difference – as he refused to believe the bank could go bust.

“That was the mistake we made; we should have taken our burning,” he said in a wide-ranging interview published in the Irish Mail on Sunday.

However, he also said he believed he and his family were the victims of a “sinister agenda” being carried out by the Irish Bank Resolution Corporation, formerly Anglo Irish Bank.

In the interview, conducted over the weekend, Mr Quinn said: “[Anglo/IBRC] have treated us like dogs and have tried to put the entire family out on the road with the sole purpose of ensuring that we would not be in a position to challenge their sinister agenda.”

He made his comments after Ms Justice Elizabeth Dunne last Friday jailed Seán Quinn jnr for three months for what she termed “outrageous” contempt of court orders, in stripping assets from their €500 million international property group.

Mr Quinn’s nephew, Peter Darragh Quinn, was also sentenced to a prison term for contempt.

Gardaí are searching for Peter Darragh Quinn – son of former GAA president Peter Quinn – after he failed to turn up for Friday’s court hearing.

In an account that at times seemed rambling and incoherent, Mr Quinn defended the investment strategy that resulted in him amassing a 28 per cent stake in Anglo Irish Bank by late 2007.

“We were making so much money that we wanted to look at [investment] opportunities . . . So we decided to put one-third of our money in manufacturing and one-third outside of Ireland in property . . . And the other one-third would go into blue-chip shares.There was no risk in blue-chips.”

Mr Quinn said he was “a fan” of Anglo, preferring it to other Irish banks. He said he had been quietly buying shares in the bank since 2005. Over time, his investment plan fell by the wayside, with the stake in Anglo taking over.

“We got sidetracked,” he said, adding: “I saw Anglo shares start falling, but I never dreamt the value would fall to where it did.”

Mr Quinn also gave a somewhat muddled account of how and why Quinn Insurance was put into administration in 2011.

“We had €1.1 billion in cash . . . We were a highly profitable company, the regulator was wrong. Which was right? Which was right, was there a lack of solvency? [Michael] McAteer [one of the Quinn Insurance administrators] was wrong,” he said.

Mr Quinn disputed that the company was insolvent after it recorded substantial losses in 2009 and 2010.

“Anglo has a bit of a vendetta against me . . . There is a vendetta or a fear. They want to bankrupt me for €3 billion and yet they haven’t proven that debt,” he said.

“There are security firms, private security firms. There is surveillance; they are calling, trying to intimidate,” he added.

Mr Quinn again disputed IBRC’s claim that members of his family owe more than €2 billion, saying their collective debt is limited to €450 million “agreed-upon” debt, which was extended for property investments.

“This [€450 million] was lent prior to September 2007, prior to the shares issue with Anglo, and all of the assets these funds were secured against are now under the control of Anglo,” he said.

“For the avoidance of any doubt, the family have not tried to dissipate any assets that the legitimate €450 million is secured on . . .

“The bank deliberately tied all borrowing in together, which is fundamentally wrong, and set about closing us down in the process,” he added.

Mr Quinn said he had encouraged his family to take steps to fight back, adding he “fully endorsed their actions”.

“They are standing up to the bank that took everything from them. This is what you do with bullies and is what I have always done,” he said.