In most cases you will not need to apply for planning permission to knock down a building, unless the council has made an article 4 direction restricting the permitted development rights that apply to demolition.
If you decide to demolish a building, even one which has suffered fire or storm damage, it does not automatically follow that you will get planning permission to build any replacement structure or to change the use of the site.
Where demolition of any kind of building is proposed, the council may wish to agree the details of how you intend to carry out the demolition and how you propose to restore the site afterwards.
You will need to apply for a formal decision on whether the council wishes to approve these details before you start demolition. This is what is called a "prior approval application" and your council will be able to explain what it involves.
Listed buildings and buildings in conservation areas
You do not normally need to make a planning application to demolish a listed building but you may need listed building consent. If the building is in a conservation area you may need planning permission for relevant demolition in a conservation area.
You should discuss this with your local planning authority before you take any decision to demolish such buildings, to avoid the risk of legal action being taken against you.