Oftentimes, the planning pre-application advice for your proposal will take anything from two to six weeks. Pre-application advice can help to ensure all the formalities are correct, and it could help save time and effort in the longer term by helping you to avoid refusals and appeals on account of technicalities.
The two to six-week period is not inclusive of the validation period, or the determination period, so pre-planning advice can increase the lead-time of your development project. However, as previously mentioned, you could save time and effort by going down this route. You may even find your proposal is for a permitted development, in which case, you could skip a planning application altogether!