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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Becoming clear and frosty overnight. Bright and dry on Monday.
An Essex councillor is appealing for help to find out what happened to her "beautiful, much-adored" daughter after she was found dead.
Frost and freezing fog overnight but milder with some rain tomorrow.