An hour is still far too long for an incident rated as "serious" though Joe. 8 minutes is the target for all emergencies, and this thing is starting to happen more and more often.
Also, its amazing how quickly and easily an incident rated as "serious" can turn into one rated as "life threatening". If someone has a bad enough epeileptic fit that an ambulance is requested for instance are automatically rated as "serious" from the off, but can quite easily become fatal if an ambulance doesnt respond quick enough.
I agree that the life threatening one should take priority, but an hour is just far too long imho, under 40 minutes should have been the target in that situation.
A LOT of the delay's are caused by ambulances being forced to wait outside hospitals with patients after booking them in, for upto 3 hours at busy times, when really the patient should be in the hospital and the ambulance should be freed to respond to other emergencies asap.