(in town and country planning) Generally, the carrying out of any building or other operation affecting land and the making of any material change in the use of any buildings or land. Development does not include alterations to buildings not materially affecting their external appearance or changes of use that fall within certain use classes prescribed by statutory instrument. For example, office use is a use class and a mere change in the type of office business is not development. All development requires planning permission, other than “permitted development” under a general development order. The demolition of houses to provide car parking and a landscaped area is not development.