Belton House has won planning approval from South Kesteven District Council to boost security at the historic Belton House.
The National Trust had applied to replace aging intruder alarm systems, install extra tv cameras and other measures.
South Kesteven District Council said: “The proposed intruder alarms are required to provide extra coverage for ‘blind spots’ and other areas not currently monitored by the existing alarms.”
The report added installation of the devices “is justified on the grounds of the need to prevent theft of or damage to historically valuable contents of the property.”
It would also be done in a way to minismise disturbance of the historic fabric of the building.
A National Trust spokesperson commented: “As far as I am aware this is part of our continuing programme of works and conservation management of the site, and not in response to any recent criminal activity at Belton.