These are defined within Schedule 1, Part 2, of the Town and Country Planning (General Permitted Development) Order 1995, under Article 1(5) and are sometimes referred to as Article 1(5) land.
Caiff y rhain eu diffinio o dan Erthygl 1(5) yn Atodlen 1, Rhan 2, o Orchymyn Cynllunio Gwlad a Thref (Datblygu Cyffredinol a Ganiateir) 1995, a chyfeirir atynt weithiau fel tir Erthygl 1(5).