The prosecution said he was engaged in a massive con. His defence team said he was answering Ireland’s call.

David Drumm, once the high-flying, free-wheeling, straight-talking boss of what was believed to be one of the country’s most successful banks, has spent almost 90 days in the criminal courts’ complex, sitting in Court 19.

The charges against him related to the dying days of Anglo Irish Bank.

He admitted he had authorised a series of transactions totalling €7.2 billion between Anglo, Irish Life and Permanent and Irish Life Assurance in September 2008. But he said he had not done this dishonestly and had not set out to commit fraud.

There was nothing dishonest either he said, in the reporting of these transactions in Anglo’s preliminary end of year results, published in December 2008.

But the court heard these were not real transactions, and the €7.2bn was not real money.

Over the course of two trials in the Circuit Criminal Court, the transactions were described as "a candy floss".

Their only purpose was to "puff up" Anglo's deposits to deceive investors, depositors and lenders about the health of the bank, the prosecution claimed. 

They were dishonest and corrupt, falsified and dressed up - a way to induce people to leave their money with Anglo, when Mr Drumm and his colleagues knew the bank was going down the tubes.

The jury was told the scheme was the result of months of arrangements and discussions and was a monumentally fraudulent criminal conspiracy – as prosecuting counsel, Mary Rose Gearty described it: "a massive con".

The transactions:

The only real money involved was a sum of £1 billion pounds sterling sourced from Anglo’s Isle of Man branch.

The money was sent from Anglo to Irish Life and Permanent and then back to Anglo as if it was a deposit from insurance company, Irish Life Assurance.

This was done a number of times "at lightning speed", in late September 2008, until it totalled €7.2bn.

It appeared in Anglo’s end of year figures as a customer deposit. Such deposits are an indicator of the health of a bank – showing that corporate entities have faith in it.

In reality, when it came to Anglo at that time, nothing could have been further from the truth. 

On 29 September, as those involved scrambled to keep the transactions going around in circles, Anglo ran out of money, and had to seek emergency funding of €1bn from the Central Bank.

The following day, the Government guarantee sparked a renewed flow of real deposits back into Anglo, but it was only a temporary reprieve.

The beginning:

Former Anglo treasury director Matt Cullen told the trial he realised there was trouble ahead, in July 2007, when the interbank market  - where banks lend to each other - started "drying up". 

Over the next few months, the situation deteriorated rapidly.

On 16 March 2008, Mr Drumm sent an email suggesting Anglo should give consideration to an initiative by the Central Bank, encouraging Irish banks to support each other. This initiative became known as the "green jersey agenda".

The day after Mr Drumm sent his email, the financial markets collapsed so spectacularly, the meltdown was dubbed the St Patrick’s Day Massacre.

Mr Cullen gave evidence that Mr Drumm asked him and others to go to their contacts in other Irish banks and talk to them in relation to helping each other out. A special committee was set up in Anglo to draw up a list of potential funding initiatives. 

There were more than 50 proposed schemes, but one by one they all fell away as the crisis worsened.

The court heard Mr Drumm needed €7bn in customer deposits to meet the targets he had decided on. By September, the only plan left to bring in the money was an agreement between Anglo and Irish Life and Permanent.

The two institutions had previously co-operated on transactions in March and June 2008, when half year figures were due to be finalised in Anglo and IL&P respectively.

The difference between those transactions, allowed as "legitimate balance sheet management" and the scheme at the centre of this trial, the prosecution claimed, was that the previous transactions involved REAL money or assets.

The conspiracy:

Mr Drumm was accused of conspiring to carry out the fraudulent transactions with colleagues – former Anglo finance director, Willie McAteer, John Bowe, formerly of Anglo’s Treasury Department as well as the former CEO of Irish Life and Permanent, Denis Casey, and others.

Their 2016 trial for the conspiracy heard Mr Drumm was the driving force behind the transactions. Mr Drumm’s own trial was told he called the shots.

The jury heard tapes of phone calls between Mr Drumm and various bankers during September 2008.

In her charge, Judge Karen O’Connor warned jurors that these were clearly very stressful and difficult times and people were under a lot of pressure. The phone calls, details of which first emerged in the media as "the Anglo tapes", showed a level of hysteria and black humour as well as arrogance and recklessness amongst the senior bankers.

On the tapes, played in court, Mr Drumm calls the Financial Regulator "Freddie F**king Fly". He describes the Central Bank and regulatory authorities as "that f**king shower of clowns down in Dame Street". 

He says Anglo is "f**ked" even if they get a "six billion euro fix" from Irish Life and Permanent and suggests Willie McAteer might have to audit the books himself.

Lawyers for Mr Drumm fought to prevent the most damning excerpts from being admitted as evidence. They said their client did not know he was being recorded.

The tapes were just a snapshot and it was unfair to pluck out these excerpts, they said. And they described the Anglo tapes as a "cultural phenomenon" that had gone around the globe.

But the prosecution argued the excerpts showed the relationship between Anglo and the regulatory authorities.

The regulator, they said, was seen by Mr Drumm as a minuscule person who went buzzing around annoying people and doing his "fly like best" to disturb the doings of those whose lives he intersected.

After the jury began their deliberations, the first thing they asked for, was to listen to the taped conversation about ‘Freddie F**king Fly’ again.

The authorities:

As in many of the other criminal proceedings begun in the aftermath of Anglo's collapse, the role of the Financial Regulator featured prominently in this case.

Mr Drumm’s lawyers argued the Regulator was aware of what was going on. And they claimed Mr Drumm was simply "togging out for Ireland" at the request of the Central Bank.

The court heard Anglo’s then head of liquidity, Ciaran McArdle spoke to the Financial Regulator’s office on 1 October 2008, after the transactions had been completed and told them the €7.2bn was "not a real number" and not to read too much into it.

In an email to former chief financial officer, Matt Moran, in January 2009, after he had left the bank, Mr Drumm said he would "relish the opportunity" to sit in front of Con Horan from the regulator’s office and ask him to tell him to his face that he "didn’t know about this". 

He said the Regulator and the Central Bank were fully aware of what Anglo was doing to protect themselves.

Willie McAteer told Mr Moran that he had discussed the transactions with the regulator, who had said "something to the effect of ‘fair play to you Willie’".

Mr Drumm’s lawyers also argued that the transactions were carried out openly and transparently without secrecy, trickery or skulduggery. They said many people in the bank knew about them and did not raise any red flags.

The Verdict:

But in the end that was all irrelevant.

An expert witness called on behalf of the prosecution said the €7.2bn transaction had no commercial substance, and its inclusion in the bank’s preliminary announcement to the stock exchange was misleading and inaccurate.

Judge Karen O’Connor told the jurors that knowledge or inaction by a regulator or audit committee cannot make something lawful if it is unlawful. 

The Regulator and Central Bank cannot condone criminal behaviour she said. Those involved may have been trying to keep the bank’s doors open, but necessity did not provide any defence to the charges.

The nine men and three women decided that the transactions were entered into dishonestly with an intention to mislead. 

They also found David Drumm knew the figures were false, misleading or deceptive when he presented them in December 2008.

What next?

Since his return from the US, Mr Drumm has been living in the house he grew up in Skerries in north county Dublin. 

Strict bail conditions were imposed at first, meaning he had to sign on twice daily at Balbriggan Garda Station - those conditions have since been slightly relaxed.

It is almost certain that he will now be going to prison, although it is not clear for how long.

Conspiracy to defraud is what is known as a "common law" offence. This means the parameters of the offence as well as the minimum and maximum sentences are not set down in legislation. 

Instead, the court has to rely on previous cases. 

Judge Martin Nolan, at the sentencing of Mr Drumm's co-conspirators, two years ago, said he believed the starting point for the sentence was eight years, before taking various mitigating factors into account.

Mr Drumm was extradited to Ireland midway through that trial.

If he had faced trial with his former colleagues, he would by now have completed a substantial chunk of any prison sentence imposed.

But the five months he spent in a maximum security prison outside Boston before finally agreeing to his extradition will be taken into account when the Circuit Criminal Court imposes its sentence in this case.