The campaign by emergency physicians to deal with hospital overcrowding began under the Labour Government. They wanted to end the use of EDs as a "warehouse" for patients waiting for admission to a ward, a practice that reached its low point in the winter of 2007 at North Shore Hospital when some patients were left in the emergency care centre for several days.
Once a patient has been accepted for admission but has not yet been shifted, the risk of reduced supervision increases because ED staff tend to focus on new arrivals.
"I certainly saw patients come to harm in Auckland Hospital before the target was brought in," said Dr Parke. "One of the things that was very helpful in moving the target along and persuading the (Government) was that each one of us from every district health board was able to say, 'Look, we've all got these stories.' It's not bad hospitals - there was a lot of focus on North Shore at the time - similar sorts of badness were going on in every department across the country."
Dr Parke's colleagues regret his departure and the loss of his straight talking.
The Health Ministry's ED target "champion", Professor Michael Ardagh, recalled Dr Parke's frankness at a meeting on how to fix the problems seen in EDs, which were caused by wider problems in hospitals.
He said the meeting was asked, "What do you want? and Tim said, 'I just want someone to give a shit'. And that's what the target does."
Originally from Ireland, Dr Parke trained in Scotland and rose to be clinical director of emergency services for two Glasgow hospitals.
"Coming from a relatively tough health system in Scotland gives you a degree of clarity. One of the things you need to do as head of (an emergency) department like that is almost be a policeman, a traffic warden.
"So, for example, people staying more than six hours is not acceptable. You just make that clear and each time it happens you make it uncomfortable for everyone else in the hospital ... the other staff."
When he arrived in New Zealand in 2005, England was coming to terms with its four-hour ED target and the scheme had just been introduced in Scotland.
"I had worked in London for a short period with the target and saw some of the things that gave me a very good idea of what not to do, such as somebody walking around with a clipboard and it gets to three hours and 55 minutes and moving the patient just for the sake of meeting the target.
"We've never done that ... We would never move someone mid-assessment (if) they were unstable, whereas there was some evidence of that happening in the UK."
In Scotland he was involved in a helicopter emergency medical service and when he returns he will divide his time between being an emergency doctor at Glasgow's Southern General Hospital and flying on an emergency medicine retrieval service serving the Scottish western islands.
He has been part of the Auckland region's two-year trial Helicopter Emergency Medicine Service, which since September 2011 has put senior doctors on Westpac rescue helicopter missions.
"Having senior doctors in the resuscitation room, working with the paramedics in the pre-hospital environment, means that some treatments can be provided that really make a difference, for example the early treatment of head injury."
Not in favour of move to clinics
Emergency specialist Dr Tim Parke is critical of an experiment to devolve some hospital treatment of the acutely sick or injured to privately owned general practices and accident and medical clinics.
The St John Ambulance service takes a small proportion of Auckland patients - around 12 a day - to GP or A&M clinics, if medically appropriate and if the patient wishes, rather than to one of the region's four public hospitals. Treatment at those clinics, including any ACC surcharge, is state-funded. The aim is to provide the most efficient and effective care and to help constrain the growth of ED attendances, which has greatly exceeded population growth.
But Dr Parke, an advocate of public health systems, sees it as an "ideological redirection" of patients towards privately owned businesses, one which risks "emasculating" public hospital emergency departments and wasting money through patients inappropriately being taken to a GP or A&M, only to be redirected to a hospital.
St John medical director Dr Tony Smith, an intensive care specialist at Auckland City Hospital, said only a few patients had been taken to an A&M clinic inappropriately; they were taken when the clinics' radiology facilities were closed.
Dr Smith said it was too soon to know if the scheme, introduced last year, was saving money.
"I recognise the view of Tim Parke that 12 patients across the city, across four (hospitals) is a very small number of patients. It means none of the emergency departments have been able to reduce their costs. The additional cost of those 12 patients is tiny, therefore there is a small amount of additional cost to the system in that they are being seen at an A&M."