An outline planning application can only be made for a new building or an alteration or extension to a building. Sometimes a developer may wish to see if a proposed development is acceptable in principle, but does not want to go to the cost of preparing detailed plans, e.g. if they want to know if a new house would be allowed on a plot and they intend to sell the plot on for somebody else to build the house. They can make what is called an outline planning application to ascertain this. The bare minimum that has to be supplied is the use(s) of the proposed building(s), the amount of development proposed and the general position(s) of the access or accesses to the site, but further information can be submitted if the applicant chooses. There are five matters which can be reserved for subsequent approval, referred to as “reserved matters”; access, appearance, landscaping, layout and scale. Further details of what these terms mean can be found in Regulation 2 of the Town and Country Planning (Development Management Procedure) (England) Order 2015.
In some circumstances an authority might not be willing to consider an outline planning application, e.g. in a Conservation Area where some or all of details of the development might be important issues. If this is the case, they have a month in which to ask the applicant to submit some or all of the reserved matters. The applicant can then either submit these or lodge an appeal to the Planning Inspectorate as if permission had been refused.
Obviously it may be more difficult for neighbours, etc to comment on an outline planning application, but they should do so if they have views to express. Once outline permission has been granted, the planning authority has to accept the principle of the development agreed on the site. When determining an outline application, the planning authority should impose any conditions relating to the principle of the development, e.g. if it is a business and they wish to control the operating hours and any of the "matters" not "reserved" for future determination. Conditions imposed at the reserved matters approval stage can only relate to the details of the development then submitted, not the principle.
More information can be found on the Planning Portal.