Paramedics in Norfolk will not be joining their colleagues who are taking part in strike action across the country today.
Ambulance workers and other NHS staff are staging a strike co-ordinated by the GMB, Unison and Unite.
It follows a dispute between union members and the government about pay and working conditions.
The impact upon services will vary by region, but extensive disruption is expected.
The East of England Ambulance Service (EEAS), which covers Bedfordshire, Hertfordshire, Essex, Norfolk, Suffolk and Cambridgeshire, will not take part in the strike action as the vote among local union members did not reach the threshold for action.
But it comes as eight out of the 10 ambulance services in England, including in the east, declared critical incidents due to the pressure services are under.
During this time, NHS services in the region will focus on patients with the greatest need.
A spokesman for the ambulance service said: "Staff will continue to work hard in challenging circumstances and respond to incidents as quickly as possible.
"If people need to contact the ambulance service due to a life-threatening condition or serious injury, they should still call 999.
"For everything else, people are encouraged to use 111 online, speak to a GP or use a minor injuries centre."
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