Does a rent guarantor have to be a homeowner?

Yes, a guarantor normally has to be a homeowner.

For most of the accommodation providers who ask for one, the guarantor must be a homeowner in the UK. This is because, in case of default, the landlord or accommodation provider wants to be able to recover rent or damages from the guarantor. A UK homeowner is much more likely to be able to pay these costs than someone with no visible assets to their name in the UK.