Phillip Hughes' ambulance given lowest emergency priority St Vincent's Hospital, where Phillip Hughes was treated. Doctors said the paramedics' arrival time was unlikely to have made a difference to Hughes' survival. The first call for an ambulance for cricketer Phillip Hughes was given the lowest level of emergency priority by the Ambulance Service, a source has revealed. Questions have been asked about why the first ambulance called for the cricketer, who died on Thursday, arrived after 23 minutes. It took a second triple-zero call before another crew of paramedics arrived, 15 minutes after the alarm was first raised. Emergency calls are ranked on an A to C scale that determines the number of paramedics assigned to a call and their skill level. The call from the SCG on Tuesday, made six minutes after Hughes' collapse, was classed C, an Ambulance Service source familiar with the matter said. "Anyone unconscious should have been classified at least a B," the source said. The Ambulance Service twice declined to "comment on this tragic incident" or respond to questions about whether the first ambulance was carrying only one paramedic. Incidents classed A indicate a patient's life is in danger. Ambulances can be reassigned immediately and sent to A-grade emergencies without approval from a senior manager. But paramedics said the closest available ambulances are usually sent to all grades of emergency call in Sydney. It is not known if the first call from the ground mentioned Hughes was unconscious. Cricket NSW and the SCG both said they could not comment. About 40 per cent of all emergency calls are given C status; 11 per cent B; and less than one per cent A. The remainder are sub-emergency calls that do not require use of sirens and lights. Even doubts about a patient's consciousness would usually see a call automatically elevated to B or A status, a source said. The second ambulance called - with the call classed as A - arrived within seven minutes, below the international benchmark of eight minutes. The paramedics' union said delays in a nearby hospital prevented nearby ambulances from being sent to the cricketer. It is not known where the first ambulance was when the call to help Hughes came, but it was usually based at the inner-west station of Summer Hill, 10 kilometres away. The union says it is likely a second, closer ambulance became available only in the eight minutes between the first and second triple-zero calls. It said paramedics near the SCG reported being kept off the road at the nearby Prince of Wales hospital. Paramedics are obliged to remain with patients in the emergency department until a bed is available. "Paramedics are telling us they are often being dispatched to casualty locations a considerable distance [away] because there are [none] available," said Wayne Flint, the president of the Australian Paramedics' Association. Doctors at a press conference on Thursday said paramedics' arrival time was unlikely to have made a difference to Hughes' survival and noted he was treated by doctors at the ground. Medical history records only 100 cases of the catastrophic injury that dissected the 25-year-old batsman's vertebral artery. Ambulance call centres were once staffed with a paramedic dispatcher in charge of "triaging" calls. They have been steadily replaced by "civilian" public servants, whose salaries are about $8000 a year less. Fairfax reported last year that fewer than half of the dispatchers in the Sydney control room were now paramedics. Demand for ambulances in NSW has grown steadily at about 4 per cent each year. The number of full-time call centre staff rose 7 per cent between 2008 and 2013. Fairfax revealed last year that callers had been on hold to the centre for 20 minutes and 13 minutes in two separate incidents. The office of the Health Minister, Jillian Skinner, said it would not be commenting on Friday.