David Drumm, the former Anglo Irish Bank chief executive, sent an email to a colleague in the bank saying that the controversial €500m Maple 10 share placement had been “squared” with the Financial Regulator.

The same transaction, whereby the bank advanced loans to 10 clients to purchase a 10% stake in the bank, is currently the focus of a garda and Office of the Director of Corporate Enforcement investigation.

A colleague of Drumm’s, Matt Moran, the chief financial officer, also sent an email saying: “Project Maple — regulator conversation done and went fine.”

The Financial Regulator later claimed that it did not know of the terms of what it called a “sweetheart” deal. It remains unclear how it could have allowed the deal to go ahead if it did not know all the aspects of it.

The Maple Project was designed to reduce businessman Sean Quinn’s financial interest in the bank. Quinn held 28% of Anglo Irish Bank through instruments known as contracts for difference.

Internal Anglo Irish Bank documents and emails, seen by The Sunday Times, show that there was significant state support for the secret placing of Quinn’s interest to prevent the bank’s share price collapsing.

As far back as March 31, 2008, Anglo told the regulator that the share placing was to ensure “the market price of the company’s shares will not be destabilised”.

The Sunday Times has unearthed communications between Anglo and the regulator which show that intimate details of the bank proposal to regularise Quinn’s holding were shared with the authorities.

The issue was also discussed at the meeting between bank executives and the regulator on March 27, 2008.

Drumm, Sean FitzPatrick, the bank’s chairman, and Willie McAteer, its finance director, met with Pat Neary, then the Financial Regulator, and Con Horan, prudential director at the regulator’s office, to discuss the issue.

On March 31, 2008, Anglo forwarded to the regulator a “memorandum of agreement” between it and the Quinn Group, on a plan to reduce Quinn’s holding. The terms of the agreement would be kept “confidential” from other shareholders in the bank.

Under that agreement, Quinn was to take a 18% stake, with holdings held individually by members of his family, and for 10% to be placed with investment funds.

The bank told the regulator in meetings that it would fund Quinn’s share purchase. The regulator did not object.

Anglo, with the knowledge of the regulator, attempted to place at least a 10% holding with institutional investors in Britain, the US and the Middle East. It could not attract any interest.

On July 8, 2008, Drumm told Moran: “Matt, I spoke to Willie [McAteer] about moving the game forward tomorrow with a select group of clients ... Time for action.”

The select group of clients were later to be known as the Maple 10, and the shares were placed on July 14, 2008.

Anglo’s “Maple deal sheet”, which governed the transaction, states clearly the share purchase by the 10 would be funded by Anglo with “personal recourse for 25%”. This meant the bank could only purse the 10 for a quarter of the €472m they were loaned.

Investigators have examined phone records and notes surrounding the discussions between Anglo and the regulator in the days before the Maple deal was finally executed on July 14.

This confirms that Morgan Stanley, an American investment bank advising Anglo, also discussed with the Financial Regulator how the deal would be executed. Morgan Stanley told the Maple 10 that the regulator had fully approved the transaction.