Although the Government has attempted to make the planning process simpler, which they have achieved by simplifying permitted development (works you can do to your house without planning permission), a new process was introduced called validation, which is carried out by Local Authorities prior to the registration of all Planning Applications. This process is a giant box ticking exercise where the planning authority will go through the documents and drawings that have been submitted, and check that all the information required is complete and accurate. Although I'm sure the planners would never use the validation process to deliberately delay registration when the planning department is under pressure, it has been known that requests for additional information  included a flood risk assessment for a utility room extension!

So gone are the days when a simple set of existing and proposed drawings and an Ordnance Survey map was enough to obtain planning permission. It's now almost standard practice to have a bat survey completed (also known as a biodiversity checklist) to accompany any planning application that involves demolition or works to existing roofs. I've always been confused why they don't just include the requirement for a bat survey prior to commencement of the building works on the planning approval, saving the applicant paying for a survey that is useless if their planning application is refused.

There is now a list of additional documents as long as a gorilla's right arm that the planning authority can request. However don't just agree and commission experts to prepare reports. Make sure that the request is reasonable first as the validation team are not planning officers. Therefore make sure that you do require the additional information by contacting the Local Authority and having a chat with the duty planning officer. This could save you a lot of money! And worth a phone call. There is no way to know what information you will be asked for. The easiest way to get an idea is look up a nearby similar project on your council's planning website and see what documents were submitted. If you are asked for more information you can also use this example to argue your case and save some cash!

Some additional reports that you may require:

1. Design and Access Statements (DAS) for new builds & extensions in conservation areas.
2. Arboricultural Impact Assessment if on your land you have trees. This will need to be completed by an Arborist and should justify that your proposals will not have an adverse affect on existing trees.
3. Ecological Survey or Biodiversity checklist if your building is set in a rural area your plot or home could house protected species such as bats. As bats are protected wildlife a survey will have to be completed. Generally the council would let you know via a letter if this has to be done before they approve your plans. Although it's now common practice and required by most Local Authorities.
4. Flood risk assessment if you property is in a flood risk area. These reports can be complex for new builds and will be sent to the Environment Agency during the application for their approval.
5. Noise mitigation report may be requested if your development is in a town or city centre.

Along with all this additional information you may or may not require depending how the validation team are feeling on the day, you need to make sure that all your plans are drawn correctly and at the right scale. Any discrepancies and the application will be returned to you, delaying registration and your decision date. You also need to make sure the forms are correctly filled out, otherwise again your application will get punted out!