Paramedics responding to a "genuine emergency" in Leicester returned to their ambulance to find this note left on their windscreen.
The handwritten note told the crew off for "blocking their driveway for 45 minutes".
East Midlands Ambulance Service (EMAS) have urged members of the public to speak to paramedics if they are blocking their access.
Lee Brentnall, Paramedic and Ambulance Operations Manager for EMAS said: “It is so disappointing to see that a rude note has yet again been left on one of our ambulances. This upsets our dedicated ambulance crews when they are trying to help our patients and do their job.
“Leaving a note will not resolve the situation as we are unlikely to see it until we are leaving in the ambulance to take the patient to hospital or to go to our next job.
He said crews are "approachable" and will move their vehicles if needed.
“However, there will be times that we are treating someone experiencing a life-threatening and time-critical emergency and moving our ambulance will not be our priority," Lee added.
"In these cases, you will need to be patient as we try to save someone’s life.”