'I think as a clinician you can impact hugely on the individual patients that you see. But ultimately there are only so many hundreds or thousands of those over a month, a year, or tens of thousands of them over a lifetime."

Professor Brendan Drumm smiles wryly when he recalls why he decided to take on what many people would deem to be the "poisoned chalice" of chief executive of what was then the newly established Health Service Executive in August 2005.

As the 54-year-old Leitrim-born paediatrician readily acknowledges, he already had an internationally successful research career and could have taken the "easy option" of remaining where he was.

Despite earning a basic salary of around €370,000 a year – which he accepts is a "very well-paid" job – he reiterates that he could have earned an awful lot more money elsewhere.

He also says that, because he took the job, his earnings will be significantly less when he returns to the twin worlds of clinical practice at Our Lady's Hospital for Sick Children in Crumlin and academia at UCD.

"I would have given up any practice I had. So for instance I would never have had a large private practice but that would all have disappeared," he explains.

Drumm clearly retains a strong sense of himself as a "maverick", an image which perhaps derives from the early days when he took over as CEO.

Far from needing to provide more hospital beds, he argued from the start that there was a need to reform a system which was based on a "1950s" model of healthcare. Many would maintain that the HSE he has led for the past five years is still a long way away from delivering such a service, with neglect of child protection a particular concern.

But he persuaded his political masters, such as health minister Mary Harney, to take what was a politically challenging route to reform. He has been "amazed by her capacity to actually continue down that road with us".

He also controversially maintains that the state would have had to hand over a "whole load of empty hospital beds" to Nama if it had proceeded with "populist" plans to provide 3,000 extra hospital beds.

"The system measured you on how often you did something and how long you did it for. So if you brought somebody into a hospital and you changed their hip, and you kept them for 14 days, you were considered to be doing a better job than the people who brought you in and got you out in seven days. So inefficiency was constantly rewarded," he says, clearly warming to what is an oft-rehearsed theme.

"Now there's been huge buy-in... And the fruits of that will be seen not only now but over the next ten or 15 years. But is it a lonely furrow to start out with? Absolutely. I mean, the most comfortable place you could be would have been to take this job and then sit on the fence and say now we need 3,000 more beds, now we need €1 billion a year more to staff those beds.

"And, by the way, we need about €3 billion in capital up front to build those beds. And I would have looked great in terms of all the new hospitals being built, I'm sure. Everybody would be very happy in the system, that we would have forced the government to give us more money. But what would we have ended up with? I mean, I would have ended up feeling like I was a very important man, I'm sure, because everybody would have liked me for that. But the system would have ended up in 2010 with a whole load of empty hospital beds that they would have had to give to Nama, because they would have nobody to staff them. They would have ended up still bringing people into hospital for twice as long as they needed to come in for. You would have ended up with no community-based structures being built up to allow people to be treated closer to home. So it would not have been the right thing to do, that's for sure."

He also suggests that many of his fellow clinicians, such as doctors, nurses and therapists, have resisted change in part due to their egos, but now support change because they have been provided for the first time with clear performance data to illustrate why it is needed.

"They meet their patients every day, and even if their patients have waited long times for their service, your patient – and I would have been a beneficiary of this – your patient or your client constantly thinks you're really very good at what you do. And they're very vulnerable when they come to you, and they're very thankful for the service they get from you. So you're constantly reinforced in how good a job you are doing, and you tend to ignore your responsibility for how the wider system operates – in other words the need to improve the processes through which we operate," he contends.

"I don't even know that they have giant egos to start with, but I think what you have is, you work in an environment where, unlike most other environments, you actually get constantly positive reinforcement. Now if you constantly get reassured as to how well you do your job, then it can be – and it's not a medical issue – it can be very difficult for you to actually deal with change as being your responsibility. In other words there's a need for you to change how you do things. I think that's one of the things we really have achieved here."

Despite the ongoing criticisms of the organisation which he leaves behind, and they are many, Drumm believes we are coming close to the point when a lot of people will no longer deem it necessary to hold private health insurance, due to improvements in the way the HSE operates.

He argues that patients who have an "acute" event such as a heart attack do not gain anything from having private insurance, with the main advantage coming from the ability to have "elective " work such as hip replacements or angiograms done more quickly.

After five years at the head of the HSE, he also envisages a time when he will no longer require private health insurance and would consider dropping his policy. He says he has "greatly downgraded" his own level of cover.

"I certainly think we are close to a point where a lot of people will exit it, and I am sure that would include people like myself," he says. "I think there is a fair chance I will when I leave the job."

One of the hardest aspects of the job for him and his family has been the loss of anonymity it involves, he confides. Almost as a parting shot, he singles out some of his more vocal critics in the media for criticism.

"I think Ireland has an issue to deal with when it actually finds itself in a situation where, you know, for instance, people in the media, and the live shows and that, who are actually making more than somebody like me... taking phonecalls from the public. I think sometimes that does get very personal but I think there is a bigger issue for the country as a whole, which is how actually it is going to run its services going forward."