Paul Remington vice chair of the East of England Ambulance trust thanks Ms Ball for her hard work.
He said: “Maria spent many years leading the ambulance service and I would like to thank her for her dedication and commitment through what have been some challenging times.
"Maria oversaw the formation of this Trust, bringing together three disparate organisations into one service, and its subsequent development."
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Remaining cold with sunny spells and further scattered rain and sleet showers. Any early snow will become restricted to hills.
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Any remaining wintry showers will ease tonight but it will stay cold and there's a risk of frost and icy patches developing.