An application for planning permission would probably cost you £335:
http://www.planningpo...ish_fees-feb_2010.pdf
You have to pay that whether the application is accepted or refused.
Most councils will almost automatically refuse an application to change the use of land from 'agricultural' (or similar) to 'residential' unless the land is within an area designated for residential development. Many travellers have bought land in rural areas with the intention of the siting their own caravans on that land. In nearly every case the local authority has ruled that living in a caravan on that land (without the planning permission which they'd not normally grant) contravenes the Town and Country Planning Acts. The travellers have been forced to remove their caravans and to return the land to its former condition (by, for example, removing any hard standing or mains services which have been installed).
Chris