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 what permissions / prior approvals are required for demolition in a conservation area can be found on the Planning Portal here, and by following the links found on this page.
Before undertaking any demolition, check with your planning department 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.