I read an article from 2011 about how to get planning permission on non-development land and it included the following ‘safer’ option:
Safer Routes: The DIY Farm/Smallholding
Another tactic open to single house-holds is to buy a suitable piece of agricultural land and submit an ‘agricultural prior notice consent form’ to the local planning office detailing the agricultural building you intend to build on your land. This is ‘permitted development’ on agricultural land and hence doesn’t need planning permission. You should receive consent within 28 days and are then entitled to commence building.
You can then legally site a temporary mobile home on the land to live in whilst you build your barn (and set up your business). Your temporary accommodation can remain in place for five years (presumably as long as you are still building your barn) during which time you need to develop your business to generate as much income as possible.
At the end of five years you apply for planning permission to build a house. You must prove that you need to live on-site in order to run your business, e.g. caring for livestock that breed all year round, and that your business generates sufficient income to support you.
Is this still correct? If so, I’d like to find out more to see if it might help my son buy some agricultural land on which to run his (animal related) business and be able to (legally) live on site and, eventually, get planning permission for a dwelling so he can continue to live there and run his business there.