As part of NHS reforms doctors will be holding the purse strings from April 1st. In a special edition of the programme Dr Mark Porter finds out what the changes actually mean in practice. He meets GPs who have already been piloting some of the ways in which health services are commissioned to find out what they will mean for services on the ground. He also hears from GPs and hospital doctors about their concerns. One doctor says implementing GP commissioning is like flying a plane while it's being built. Why are GPs concerned and what could the changes mean for the future of our health services?