Detective Chief Superintendent John McMahon, head of the Special Detective Unit, has notified Garda HQ he intends to leave, as he is reaching the compulsory retirement age of 60.
The loss of Chief Supt McMahon, who had also headed the Garda National Drugs Unit and the National Bureau of Criminal Investigation, is seen as a significant blow to the force.
Sources said this is particularly so given the lack of experienced officers available to fill specialised roles. It comes as another experienced criminal investigator, Detective Inspector Kieran Houlihan, left last Friday as a result of mandatory retirement.
Det Insp Houlihan, based in the Dublin Northern Region, was highly regarded by colleagues and was leading several serious investigations at the time he had to leave. These retirements follow the shock announcement a week ago of the departure, for different reasons, of Assistant Commissioner Derek Byrne in October.
Asst Comm Byrne is the head of the National Support Services, which oversee the work of all the serious crime units. He made his decision after he secured a high- profile policing position in the Cayman Islands.
Many of these retirements raise again the issue of compulsory retirement at 60 — compared to 65 for the rest of the public service.
A number of senior gardaí are concerned at the loss of experience, and said the situation is only set to worsen in the coming year.
“Next year there will be a significant number of senior people who will be obliged to retire,” one source said.
A second source said: “A whole cohort are hitting 60 in the coming year. Most of them are in senior positions and most probably want to stay on, but can’t.”
The issue has been the subject of challenges, most prominently in a High Court case taken in 2008 by then assistant commissioner Martin Donnellan.
The judge ruled the State is entitled to maintain the retirement age. The State argued the retirement age was necessary to ensure talented younger people could move through the ranks.
A separate source said there are “pros and cons” to the retirement age, but suggested that circumstances might be different now and that the issue could be re-examined.
Another source said the problem is that recruitment came in batches so that retirements hit the force “in waves”, and that the issue is a “structural one”. Numerous sources said “succession planning” is not there to replace people due to retire.
One idea suggested is that the Garda Commissioner could set up a panel of people who are retiring — and who want to stay on — and take them in under contract as needed, as happens in teaching and the HSE.
A Department of Justice spokesman said there are no plans to change the current retirement age.