Details have emerged of the deal reached with the Government that allowed the 58-year-old to avail of early retirement with a €225,000 lump sum and an annual pension of €73,000.

Correspondence obtained under the Freedom of Information Act shows Mr Appleby may not have been entitled to early retirement as director of corporate enforcement because it was an “unestablished post” in the civil service.

He went back to being a principal officer in the civil service for 24 hours before being re-appointed as the acting director for six months.

He was allowed to use his director’s salary of €150,712, rather than a principal officer’s rate of €92,672, to calculate his pension entitlements.

The arrangement was outlined by Mr Appleby when he wrote to the personnel officer at the Department of Enterprise on Jan 16 to inform her of his plans.

“I will write to Minister Bruton on Jan 27 next notifying my intentions to resign from the position as director of corporate enforcement on Feb 28 next and to retire as a principal from the department the following day,” he said.

“I will retain my director’s salary on a personal basis for Feb 29 and will retire with superannuation benefits based on my director’s salary of €150,712 under the cost neutral early retirement scheme.”

A spokesperson for the Department of Public Expenditure and Reform said it was purely procedural that he would resign from the director’s position before retiring from the civil service.

An email to the Department of Public Expenditure and Reform from the Department of Enterprise’s personnel officer on Feb 2 stated: “We discussed yesterday the position in relation to Mr Appleby’s superannuation entitlements.

“His contract as director stated that the post of director was an unestablished post. The contract also gave him the right to retain the director’s salary on a personal basis should he cease to be the director and return to the department as a principal officer.

“Given that all unestablished posts carry a minimum pension age of 65, Mr Appleby chose to resign as director prior to his retirement from the civil service.”

The correspondence also shows that Mr Appleby met Enterprise Minister Richard Bruton the day before the Cabinet was informed of his decision to retire.

Minutes of the meeting show he told the minister that “ there were a number of staff in his office that could effectively assume the director position in an acting capacity pending the outcome of the recruitment process to fill the director’s position”.

When the Cabinet learned of the decision the next day, it was agreed to ask him to stay on for a further six months to oversee the Anglo inquiry.

When Mr Appleby took the job in 2001, his contract stated that in the event of the appointment being terminated he would be entitled to return to a principal officer post in the Department of Enterprise. In returning to the civil service, he would be allowed to retain the director salary “on a personal basis and thus be entitled to superannuation benefits based on the latter salary” according to the correspondence relating to his retirement.