The Trust has released a statement saying Maria Ball has resigned with immediate effect.
The process for appointing a new or interim chair will be started immediately but in the meantime Paul Remington who is vice chair will lead the organisation with Andrew Morgan, the interim chief executive.
More top news
Her parents describe it as her "moment of madness" - when 20-year-old Amy Vigus took the drug ecstasy while at a music festival.
Essex Cricket have announced that their new head coach will be Anthony McGrath.
Work's begun to salvage the crashed Airlander 10 after it came down in Bedfordshire.