Mr Barnett, who lived in Dunwich, was well known for his campaigning against nuclear energy and the Sizewell B development.
Mr Barnett died on Friday after a short illness, he was 93.
At the time of his death Mr Barnett remained the chairman of the Shut Down Sizewell Campaign which he had founded over 30 years ago.
He was a lifetime member of the Campaign for Nuclear Disarmament or CND: taking part in protests, lobbying Parliament and endlessly campaigning against nuclear weapons and nuclear energy.
Tom Griffith-Jones from Shut Down Sizewell said: “Charles Barnett was a man of strong principles with a deep concern for the well-being of the world and its inhabitants.”
Mr Barnett leaves three sons, nine grandchildren and six great grandchildren.
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