People and organisations should check if they have the defibrillator models, LIFEPAK CR Plus and LIFEPAK EXPRESS Automatic External Defibrillators (AED), as an electrical fault with some of them may not deliver an electric shock to the heart to someone who is in cardiac arrest. It is believed that 2,577 devices are defective. https://www.gov.uk/government/news/faulty-defibrillator-warning