GPs are among the most trusted and respected of all professions. They are our first port of call for most NHS treatment with 800,000 people visiting surgeries every day. But Dispatches reveals that failing doctors routinely slip through the system. We've been filming secretly in GP practices and have uncovered concerning evidence of misdiagnosis by doctors who have failed in the past, but are still practising. Reporter Jon Snow reveals that, six years after The Shipman Inquiry called for increased scrutiny of doctors, GPs who've been sanctioned by the authorities in the past are not regularly checked to make sure they are safe to practice. Even GPs who've been punished by the authorities in the past are not regularly checked to make sure they are safe to practice. Jon Snow also speaks to a whistleblowing doctor and nurse who reveal that even when the authorities have serious concerns about a doctor's fitness to practice they don't always act promptly to alert all patients. They allege they have been barred from telling patients the truth about serious malpractice at a surgery they worked at. As the government prepares to hand over more control and responsibility to Britain's GPs Dispatches asks how much we are really told about the medical competence of our own doctors.