There is two fold process to obtaining Building Regulations. First, plans should be submitted for approval by the local authority's Building Control Department. Once the plans are approved and assuming no objection is made to the plans within a given time period, and if the work is carried out in accordance with the plans, then according to the law no further action need be taken.
It is important however to be able to demonstrate to a purchaser and their lender that the work was properly completed and therefore the second stage of the building regulations approval process is to obtain a Building Regulations Certificate.
This certificate issued by the local authority's building inspector confirms that the work complies with Building Regulations.
Depending on the scale of the work the inspector may need to visit the site several times at several stages, for example if a new house is being built he or she will want to see the foundations, the drains etc. as well as the finished building.