The Queen actress fears schools across the U.K. are ill-equipped for heart-related emergencies - and headmasters and mistresses need to review their policies and make sure they have the right equipment.
She tells The One Show, ""Every school should have a defibrillator and people who are trained in CPR.""
It's a subject close to Mirren's heart after she discovered a friend suffered a heart attack while attending one of her film premieres.
She adds, ""A young friend of mine was at the premiere of my film The Debt, which was about two to three months ago (Sep11), and I was off doing my thing having my photo taken.
""Towards the end of the evening a friend came up to me and said, 'Chris has had a cardiac arrest and is in hospital'. Honestly, it was kind of a miracle. When you have a premiere you have medical staff at hand.
""Also, what I learned subsequently was these paramedics were from an organisation called Voluntary Response Organisation, which are volunteers who have learned CPR, first aid and can use a defibrillator. It's an amazing organisation.""