Answer

By Your Horse

Solicitor Martin Pate advises:

There’s been a lot of talk about this topic and, to a degree, the position remains unclear. The first thing to consider is what use the land has been categorized as. Land ceases to be agricultural when you begin importing feed onto it, erecting stables and exercising horses on it. Consequently, a ‘change of use’ would have taken place.
A balance needs to be struck between the primary use of the field – grazing – and the ancillary use of the land – exercising horses. If the field is generally used for grazing, but occasionally to jump in, it could be argued that no change of use has occurred. However, if the field has permanent obstacles and is no longer grazed, change of use is likely. This would require planning permission.
Other factors to be considered include whether you’re trading as a business, eg a riding school. If so, planning permission is probably needed. You should also consider if the jumps could be regarded as an eyesore.
The decision whether planning permission is needed for exercising and jumping horses on the land lies with your local planning authority. If you’re uncertain, seek advice from them. If it’s possible to prove that the field has been used predominately to exercise and jump horses for more than 10 years, it would be possible to apply for a Certificate of Lawfulness for existing use.
The fee for an application for planning permission costs around £150 to £250, and retrospective planning can also be sought. Application forms can be obtained from your local planning authority.
Finally, as the land is rented, check with the owner before you use the field for schooling and jumping.