Section 80 of the Building Act 1984 requires anyone intending to demolish a building (or part of a building) to give advance notification to the local authority in which the building stands. Exceptions are where the building is less than 1750 cubic feet, or if the demolition only involves internal parts of a building, or certain agricultural buildings. 

When we receive a demolition notice, we send a list of requirements detailing how the demolition should be carried out.

You may also need planning permission for your proposed work, especially if the building is listed or within a conservation area.