Police have released a recording of a 999 caller who required life-saving treatment but could not speak.
Quick-thinking call-handler Kathryn Longstaff realised the patient was tapping on his phone to communicate and managed to get a paramedic to his door.
The 63-year-old man rang the emergency services but could not say what was wrong after he suffered a medical episode.
Ms Longstaff, an employee of the Sopra Steria firm who is based at Cleveland Police’s Control Room in Middlesbrough, heard him tap and asked him to communicate his “yes” or “no” answers to a series of questions by knocking on his phone.
She said: “As soon as I picked up the call, I knew something wasn’t right and I had to think quickly of a way to communicate with him as I didn’t know at that point what sort of danger he was in.
“Thankfully he had contacted police before and his number and address were already on our system.
“This allowed me to ask him to confirm his personal details by tapping.
“I then asked if he was in danger and if he needed an ambulance.
“I even asked him if he could manage to open the door to allow medical services to access his house, which he was able to do.”
A Medicar vehicle staffed by two special constables and a paramedic was directed to his home and he was rushed to the James Cook University Hospital in Middlesbrough.
The patient was later able to express his gratitude by writing his thanks on a white board.
Head of force control room Superintendent Emily Harrison said: “Kathryn is an absolute credit to the force, without her quick-thinking the man might not be alive today.”