There are many criteria describing when planning permission is required. The likelihood is that if you are building something completely from scratch, making a significant change or modification to an existing building, or are looking to change the purpose of a building, then you will most likely require planning permission.
In order to apply for planning permission, you should get in touch with your Local Planning Authority through your local council. If you are doing this yourself, please be aware that if it transpires that your project requires planning permission, and you commence or carry out work without getting planning permission, you could be ordered to undo all the work you have done with an enforcement notice.
At Wilkinson Planning, we are experts in applying for planning permission for projects from building sheds at the end of a garden, through to housing estate developments.