From a medical point of view, interhospital transfers are totally different from primary work - as different as an ITU from an A and E department. Critically ill ITU patients need sophisticated ventilators (yes a transport ventilator will cope perhaps for a short time but may further damage the lungs) plus multiple infusion pumps (yes we might keep the patient alive with fewer for an hour or so with fingers crossed) and loads of other gear. It needs proper power and gases plus a dedicated fit plus size - S76 upwards.
This needs 2-3 ships for England and Wales, ideally IFR but that needs IFR approaches plus proper pads for all acute hospitals. The current debacle with GPS approaches makes the former unlikely whilst 25 years after it was made mandatory to plan helipads for new hospital builds less than 10% of new builds have pads.
Primary is still unproven despite the Sheffield review and attempts at audit. In rural areas helicopters MAY offer advantages in terms of time to hospital but in most other areas the benefits may relate to delivery of medical teams, which is why London's HEMS, which carries a doctor, albeit highly protocolised, has the edge over many others. Poland played with single engine machines to simply deliver a doctor and despite much ridicule their data is as good as ours!
We desperately need better research into primary HEMS, but I doubt night or IFR operations will ever be viable which means we doctors need to continue to develop alternatives for night and poor vis periods. The resulting development of prehospital practitioners unfortunately demonstrates a much cheaper alternative for most urban and semirural communities.
However, the cost issue is really just another political smokescreen. The cost of interhospital has been proven to save money. The cost of primary represents less than 1% of acute services and even with a life saved:missions flown ratio of 1% is a no brainer.
Given an option, we doctors would like to see 2-3 secondary and 13 primary aircraft for England and Wales, not limited to individual NHS regions, staffed with doctors and funded from central taxation.
Oh well, back to reality - well done all you fund raisers, and yes, if we cant have better a joint role with police gets my vote. Just be aware of the limitations and ensure the politicians are brought to task as often as possible.