What are the NHS ambulance response categories?

It is expected that only category 1 cases will be responded to during the strike in England and Wales

Ambulances in some parts of England and Wales will be sent out only to patients at immediate risk of dying when staff strike on Wednesday - although ministers are spending Tuesday trying to persuade them to respond to more calls.

Ambulance services in different areas are taking slightly different approaches to the 24-hour strike period, but there is a broad expectation that only the most urgent calls, known as category 1 emergencies, will be responded to.