A 59-year-old man collapsed and was given CPR outside Wenzel’s in Watford earlier today.
Paramedics and an air ambulance attended and called police for assistance shortly before 12.30pm today.
One witness walking past Charter Place saw first responders tapping the man on his shoulder.
He said: "I walked past again 15 minutes later, paramedics were performing chest compressions on him and a screen had been put up."
Police spokeswoman Sarah Spence said: "We were called by ambulance at 12.26pm to a 59-year-old man who had collapsed outside the bakers.
"The heli-med team were in attendance, they landed at the girls grammar school."
The man has been taken by helicopter to Harefield Hospital.