Enabling development which seeks to secure the preservation and/or appropriate alternative use of a listed building, or a building which makes a significant positive contribution to the character of a conservation area, historic landscape or parks and gardens of special historic interest will only be permitted where:

1. It is essential to secure the long term future of the building or historic park or garden.
2. It does not materially harm the building it is seeking to assist or its setting or the conservation area, or historic landscape, or historic park or garden in which it lies.
3. It is of a scale that is the minimum necessary to secure the preservation and/or appropriate use of the building or historic park or garden.
4. Sufficient financial subsidy is not available from any other source.