Private paramedics are being hired at a cost of up to £84 an hour to take the strain off under-resourced NHS ambulance services.
Unions say the crew get up to seven times more than health service workers.
East Midlands Ambulance Service spent £4.2million on private crews in 2013-14 .
Dia Chakavarty of the Taxpayers’ Alliance said: “We simply cannot afford this sort of waste in the NHS.”
Planned strikes by Unison, the GMB and Unite over pay have been suspended after a breakthrough in talks.