Buildings or structures within a Conservation Area are subject to stricter controls over demolition. It is an offence to undertake demolition of an unlisted building without the necessary planning permission.
Further guidance on Planning permission for relevant demolition in a Conservation Area can be found on the Planning Portal website.
Before undertaking any demolition, check with your local planning authority to see if permission is required.
Permission for demolition in Conservation Areas used to be referred to as "Conservation Area Consent", so if you are looking at older planning records (prior to 2013) you may encounter this term.