The folly has been a part of the Leicestershire skyline since 1784.
A fundraising page has been created to preserve and restore Old John Tower at Bradgate Park.
The Bradgate Park Trust has said it is investing £10k of its reserves into the work but needs the public's help to raise the remaining £20K.
Bradgate Park Trust, said: "Vulnerable to the forces of natural erosion, decay, and damage, this treasured Grade II listed building needs immediate attention to prevent deterioration of its historic fabric.
"Every penny of your donation will go towards restoring Old John Tower, paying for essential lime mortar pointing, consolidation to cracks, and repairs to the roof. We need your help to ensure repairs happen before it’s too late."
Bradgate Park Trust is a registered charity that looks after over 1,000 acres of historic parkland.
The trust has stated that if the total amount of donations exceeds the initial target outlined for the Old John Tower repairs, all further donations will be spent on the conservation and maintenance of the Park, in line with the Trust's charitable objectives.
Link to the fundraising page
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