Former billionaire businessman Seán Quinn has acknowledged his own role in the financial collapse of his one-time corporate empire.

In the second part of a three-part documentary screened by RTÉ, he talked about the huge gamble he took on bank shares which ultimately bankrupted his companies.

"I made a lot of awful good decisions in my 40-odd years of business, but that was one bad one, one fatal one," he said.

The second part of the series, Quinn Country, focused on the collapse of the Quinn Group - a huge business empire employing thousands of people along the Cavan/Fermanagh border.

The group was a network of companies involved in everything from cement and glass manufacturing to insurance.

The programme looked at Seán Quinn's decision to buy large numbers of share options in Anglo Irish Bank.

Under the so-called Contracts for Difference scheme, if the share price dropped, an investor had to provide cash to make up the shortfall.

Mr Quinn continued to buy them even as the share price slid due to the 2008 international banking crisis.

He said he had been confident that shares would recover.

He continued to take a financial position despite senior Anglo executives telling him not to - at one point holding options for more than 25% of it.

"That was wrong. I shouldn't have done that. There is no excuse for that, it was stupid to increase it at all," he told the programme.

Mr Quinn used Quinn Group money to cover his losses. He eventually ended up owing Anglo Irish €2.8bn.

When the bank was nationalised by the government, that liability passed to the Irish taxpayer.

The Quinn Group was eventually taken over by its new bankers and Mr Quinn was forced to relinquish control.

Former Fine Gael Finance Minister Alan Dukes was put on the board of the directors which took over the running of the nationalised bank.

They were instrumental in removing Mr Quinn.

"He proved to be absolutely opposed to any kind of restructuring that didn't have him at the centre of it, " Mr Dukes told the programme.

"So, it came to the point where we just took the view that he couldn't be involved."

Episode 3 of Quinn Country will be broadcast at 9:35pm on RTÉ One on Wednesday and will be available to stream on the RTÉ Player.